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United States Government Accountability Office: 
GAO: 

Report to Congressional Requesters: 

September 2011: 

Airline Passenger Protections: 

More Data and Analysis Needed to Understand Effects of Flight Delays: 

GAO-11-733: 

GAO Highlights: 

Highlights of GAO-11-733, a report to congressional requesters. 

Why GAO Did This Study: 

Flight delays and cancellations are disruptive and costly for 
passengers, airlines, and the economy. Long tarmac delays have created 
hardships for some passengers. To enhance passenger protections in the 
event of flight disruptions, the U.S. Department of Transportation 
(DOT) recently introduced passenger protection regulations, including 
a rule that took effect in April 2010 designed to prevent tarmac 
delays more than 3 hours (the tarmac delay rule), as well as other 
efforts to improve passenger welfare. As requested, this report 
addresses (1) whether flight delays and cancellations differ by 
community size; (2) how DOT’s tarmac delay rule has affected 
passengers and airlines; and (3) how passenger protection requirements 
in the United States, Canada, and the European Union (EU) affect 
passengers and airlines. GAO analyzed DOT data, including through the 
use of regression models, as well as data from FlightStats, a private 
source of flight performance information. GAO also reviewed documents 
and interviewed government, airline, and consumer group officials in 
the United States, Canada, and the EU. 

What GAO Found: 

Airports in rural communities have higher rates of delays and 
cancellations than airports in larger communities, but DOT data 
provide an incomplete picture of this difference. DOT’s data include 
flights operated by the largest airlines, representing about 70 
percent of all scheduled flights. GAO analysis of FlightStats data, 
representing about 98 percent of all scheduled flights, show more 
substantial differences in flight performance trends by community size 
than DOT data. DOT has historically not collected data from smaller 
airlines because of the burden it could impose on these airlines, but 
without this information, DOT cannot fully achieve the purpose of 
providing consumers with information on airlines’ quality of service. 

DOT’s tarmac delay rule has nearly eliminated tarmac delays of more 
than 3 hours (180 minutes), declining from 693 to 20 incidents in the 
12 months following the introduction of the rule in April 2010. While 
this has reduced the hardship of long on-board delays for some 
passengers, GAO analysis suggests the rule is also correlated with a 
greater likelihood of flight cancellations. Such cancellations can 
lead to long overall passenger travel times. Airlines and other 
aviation stakeholders maintain that the tarmac delay rule has changed 
airline decision-making in ways that could make cancellations more 
likely. To test this claim, GAO developed two regression models, which 
controlled for a variety of factors that can cause cancellations and 
measured whether the time period following the imposition of the 
tarmac delay rule is correlated with an increase in cancellations. The 
two models assessed flights canceled before and after leaving the 
gate, for the same 5 months (May through September) in 2009 and 2010. 
In both cases, GAO found that there was an increased likelihood of 
cancellation in 2010 compared to 2009 (see table). 

Table: Percent Difference in Likelihood of Flight Cancellation 

Time on tarmac: Before taxi out (at gate); 
Increased likelihood of cancellation in 2010 compared to 2009: 24 
percent more likely. 

Time on tarmac: 1–60 minutes; 
Increased likelihood of cancellation in 2010 compared to 2009: 31 
percent more likely. 

Time on tarmac: 61–120 minutes; 
Increased likelihood of cancellation in 2010 compared to 2009: More 
than twice as likely (214 percent). 

Time on tarmac: 121–180 minutes; 
Increased likelihood of cancellation in 2010 compared to 2009: More 
than 3 times as likely (359 percent). 

Source: GAO analysis of DOT data. 

[End of table] 

EU requirements provide airline passengers with more extensive 
protections, such as care and compensation, for flight delays, 
cancellations, and denied boardings than do U.S. or Canadian 
requirements. But these protections may also increase costs for 
airlines and passengers. For example, some airline officials in the 
United States and the EU told GAO that increases in the amount of 
denied boarding compensation has increased their overall costs. 
Additionally, enhanced passenger protections, such as those in the EU, 
can create enforcement challenges if regulations are unclear or not 
universally enforced. 

What GAO Recommends: 

GAO recommends that DOT collect and publicize more comprehensive data 
on airlines’ on-time performance and assess the full range of the 
tarmac delay rule’s costs and benefits and, if warranted, refine the 
rule’s requirements and implementation. DOT did not comment directly 
on the recommendations, but indicated that it would soon begin a study 
of the effect of the tarmac delay rule. 

View [hyperlink, http://www.gao.gov/products/GAO-11-733] or key 
components. For more information, contact Susan Fleming at (202) 512-
2834 or flemings@gao.gov. 

[End of section] 

Contents: 

Letter: 

Background: 

Airports in Rural Communities Have Higher Rates of Delays, 
Cancellations, and Diversions than Larger Communities, but DOT Data 
Provide an Incomplete Picture of These Trends: 

New Rule Has Nearly Eliminated Long Tarmac Delays but is Correlated 
with an Increase in the Likelihood of Flight Cancellations: 

EU Requirements Provide More Comprehensive Passenger Protections, but 
May Also Increase Costs for Airlines and Passengers: 

Conclusions: 

Recommendations for Executive Action: 

Agency Comments and Our Evaluation: 

Appendix I: Objectives, Scope, and Methodology: 

Appendix II: Delay, Cancellation, and Diversion Trends: 

Appendix III: Tarmac Delay Trends Since 2004: 

Appendix IV: Tarmac Delay Trends since October 2008: 

Appendix V: Tarmac Delay Logistic Regression Analysis: 

Appendix VI: GAO Contact and Staff Acknowledgments: 

Tables: 

Table 1: Cancellations by Stage of Flight, May-September 2009 and 2010: 

Table 2: Percent Difference in Likelihood of Flight Cancellation after 
Implementation of Tarmac Delay Rule: 

Table 3: Comparison of Governmental Requirements in the United States, 
Canada, and the EU of Benefits Provided to Passengers by Airlines 
during Flight Disruptions: 

Table 4: Comparison of Contract of Benefits That May be Provided Under 
Domestic Carriage Provisions for Flight Delays and Cancellations for 
Selected U.S. Airlines, as of June 2011: 

Table 5: U.S. Stakeholders Interviewed: 

Table 6: Canadian Stakeholders Interviewed: 

Table 7: European Stakeholders Interviewed: 

Table 8: Total Number of Tarmac Delays of More than 3 Hours by Stage 
of Operation, January 2004-September 2010: 

Table 9: Total Number of Tarmac Delays of More than 3 Hours at 35 
Airports and Systemwide, January 2004-September 2010: 

Table 10: Total Number of Tarmac Delays of More than 3 Hours by Day of 
the Week, January 2004-September 2010: 

Table 11: Total Number of Tarmac Delays of More than 3 Hours by Hour, 
January 2004-September 2010: 

Table 12: Tarmac Delays of More than 3 Hours, October 2008-December 
2010: 

Table 13: Tarmac Delays of More than 3 Hours, May 2010-April 2011: 

Table 14: Unadjusted Odds Ratio for Tarmac Cancellation, 2010 versus 
2009: 

Table 15: Unadjusted Odds Ratio for Tarmac Cancellation, 2010 versus 
2009, by Time Spent on Tarmac: 

Table 16: Unadjusted Odds Ratio for Gate Cancellation, 2010 versus 
2009: 

Table 17: Variables and Data Sources: 

Table 18: Odds Ratios Estimates for Variables of Interest in Tarmac- 
Cancellation Model, 2010 versus 2009: 

Table 19: Logistic Regression Results for Tarmac-Cancellation Model 
and Other Independent Variables: 

Table 20: Logistic Regression Results for Gate-Cancellation Model and 
Other Independent Variables: 

Figures: 

Figure 1: Percentages of Delayed, Canceled, and Diverted Arrival 
Flights Systemwide, Calendar Years 2004-2010: 

Figure 2: Percentage of Canceled or Diverted Departures by Community 
Size in 2010: 

Figure 3: Percentage of Delayed Arrivals by Community Size and 
Systemwide in 2010: 

Figure 4: Percentage of Delayed, Canceled, and Diverted Arrivals by 
Community Size in 2010 for DOT and FlightStats Data: 

Figure 5: Examples of Sources of Delay by Community Size: 

Figure 6: Tarmac Delays of More than 3 Hours during Taxi-Out and Taxi- 
In by Year, January 2004-September 2010: 

Figure 7: Total Tarmac Delays of More than 3 Hours (180 minutes) by 
Minutes of Delay, January 2004-September 2010: 

Figure 8: Total Flights on the Tarmac of More than 1 Hour During Taxi- 
Out, May-September 2009 and 2010: 

Figure 9: Domestic Airlines' Decision-Making Timeline for Flights 
Experiencing a Taxi-Out Delay on the Airport Tarmac: 

Figure 10: Voluntary and Involuntary Denied Boardings in the United 
States as a Percentage of Total Passengers, Calendar Years 2004-2010: 

Figure 11: Airline Passenger Complaint Process in the United States, 
Canada, and the EU: 

Figure 12: Percentage of Departure Flights Canceled and Diverted by 
Community Size, Calendar Years 2005-2010: 

Figure 13: Percentage of Arrival Flights Canceled and Diverted by 
Community Size, Calendar Years 2005-2010: 

Figure 14: Percentage of Delayed Departure Flights by Community Size, 
Calendar Years 2006-2010: 

Figure 15: Percentage of Delayed Arrival Flights by Community Size, 
Calendar Years 2006-2010: 

Figure 16: Airline-Reported Sources of Delay in Calendar Year 2010: 

Figure 17: Airline-Reported Sources of Cancellations in Calendar Year 
2010: 

Figure 18: Total Number of Tarmac Delays of More than 3 Hours by 
Month, January 2004-September 2010: 

Figure 19: Airline-Reported Sources of Delay for all Tarmac Delays of 
More than 3 Hours, January 2004-September 2010: 

Figure 20: Odds of Cancellation for Flights on the Tarmac, 2010 and 
2009: 

Abbreviations: 

ASQP: Airline Service Quality Performance: 

BTS: Bureau of Transportation Statistics: 

Commission: European Commission: 

CTA: Canadian Transportation Agency: 

DOT: U.S. Department of Transportation: 

ECJ: European Court of Justice: 

EU: European Union: 

FAA: Federal Aviation Administration: 

IG: Department of Transportation Office of Inspector General: 

UK: United Kingdom: 

[End of section] 

United States Government Accountability Office: 
Washington, DC 20548: 

September 7, 2011: 

The Honorable Nick J. Rahall, II: 
Ranking Member: 
Committee on Transportation and Infrastructure: 
House of Representatives: 

The Honorable Peter A. DeFazio: 
Ranking Member: 
Subcommittee on Highways and Transit: 
Committee on Transportation and Infrastructure: 
House of Representatives: 

Flight disruptions, including delays, cancellations, long tarmac 
delays, and denied boarding, are costly for passengers, airlines, and 
the economy. In recent years, roughly a quarter of all commercial 
flights have been delayed or canceled, resulting in tens of thousands 
of years in total delayed travel time and billions of dollars in out- 
of-pocket expenses and time lost for passengers each year.[Footnote 1] 
With fewer empty seats than ever, opportunities for rebooking are 
often limited, exacerbating the disruptions and associated costs. 
Furthermore, these disruptions may be particularly challenging for 
smaller communities that have infrequent service. In a relatively few 
but widely publicized cases, long delays have occurred on the tarmac 
where passengers were held on planes for hours.[Footnote 2] Passengers 
also can find themselves stranded or delayed when they are denied 
boarding because an airline has overbooked a flight. 

In the United States, airlines are generally not required to 
compensate passengers for their time or expenses when flights are 
delayed or canceled. In the European Union (EU), however, a regulation 
enacted[Footnote 3] in 2004 guarantees care, such as lodging and 
meals, and financial compensation for passengers with disrupted travel 
plans.[Footnote 4] Canada has promoted guidelines to encourage 
airlines to improve passenger protections, but has not otherwise 
required airlines to provide passenger care or compensation for flight 
disruptions. The U.S. Department of Transportation (DOT) has 
implemented some other passenger protections, including a recent 
regulation designed to mitigate hardships for airline passengers 
during long tarmac delays (the tarmac delay rule).[Footnote 5] 

You asked us to examine the extent of passenger protections in the 
United States, Canada, and the European Union (EU), as well as assess 
the trends in delays and cancellations in different-sized U.S. 
communities. We also assessed the effect of DOT's tarmac delay rule. 
Accordingly, this report addresses the following questions: (1) Do the 
trends in and reasons for flight delays and cancellations in the 
United States differ for smaller and larger communities? (2) How has 
DOT's tarmac delay rule affected passengers and airlines? (3) How have 
the requirements and practices for protecting passengers from flight 
delays, cancellations, and denied boardings in the United States, 
Canada, and the EU affected passengers and airlines? 

To identify and compare the trends in and reasons for flight delays 
and cancellations in different-sized U.S. communities, we analyzed 
data from DOT and FlightStats, a private data source from Conducive 
Technology that records flight performance information. Specifically, 
we compared the delay, cancellation, and diversion rates for all 
scheduled flights at different-sized airports and communities from 
2005 to 2010. To better understand the reason for different trends, we 
reviewed a DOT Office of Inspector General report and interviewed 
aviation industry experts; representatives of industry associations 
and consumer groups; and representatives of the three biggest U.S. 
legacy airlines and three biggest low-cost airlines, based on 
passenger enplanements. To assess the extent to which the 
implementation of DOT's tarmac delay rule was associated with an 
increase in cancellations, we examined DOT data on tarmac delay trends 
and also constructed two multivariate logistic regression models. 
Incorporating data from DOT, the Federal Aviation Administration 
(FAA), and the National Oceanic and Atmospheric Administration, the 
regression models controlled for factors that can lead to flight 
cancellations, including weather, to assess how the rule's 
implementation affected the likelihood of flight cancellations. Two 
aviation industry experts assessed our models' structure and provided 
feedback that we incorporated into our approach as appropriate. We 
also spoke with representatives of U.S. airlines, industry 
associations, consumer groups, and DOT about the rule's impact on 
passengers and airlines. To assess the reliability of DOT and 
FlightStats data, we reviewed existing documentation related to the 
data sources and interviewed knowledgeable officials at DOT and 
FlightStats about the data. We determined that the data were 
sufficiently reliable for the purposes of this report. To determine 
how the requirements and practices for protecting passengers from 
flight delays, cancellations, and denied boardings in the United 
States, Canada, and the EU have affected passengers and airlines, we 
examined the laws, regulations, international agreements, and 
voluntary commitments governing passenger protections in the three 
regions. We also reviewed the contracts of carriage for selected 
airlines in the three regions and examined DOT data on denied 
boardings in the United States. Furthermore, we interviewed airline, 
industry association, consumer group, and government officials in all 
three regions. 

We conducted this performance audit from August 2010 through September 
2011 in accordance with generally accepted government auditing 
standards. Those standards require that we plan and perform the audit 
to obtain sufficient, appropriate evidence to provide a reasonable 
basis for our findings and conclusions based on our audit objectives. 
We believe that the evidence obtained provides a reasonable basis for 
our findings and conclusions based on our audit objectives. See 
appendix I for more information on our scope and methodology. 

Background: 

The U.S. passenger airline industry is principally composed of legacy, 
regional, and low-cost airlines. Legacy (sometimes called network) 
airlines support large, complex hub-and-spoke operations with 
thousands of employees and hundreds of aircraft (of various types), 
with flights to domestic communities of all sizes as well as to 
international destinations.[Footnote 6] Generally, regional airlines 
operate smaller aircraft than legacy airlines--turboprops or regional 
jets with up to 100 seats--and often operate flights marketed by a 
legacy airline.[Footnote 7] Low-cost airlines generally entered the 
marketplace after the U.S. airline industry was deregulated in 1978 
and typically have a less extensive network and lower operating costs. 

Passengers access flights offered by these various airlines in the 
United States through hundreds of commercial-service airports. 
[Footnote 8] Primary airports are classified on the basis of passenger 
traffic as large, medium, small, and nonhub.[Footnote 9] Passenger 
traffic at these airports is highly concentrated: about 70 percent of 
passengers enplaned at the 29 largest airports and another 19 percent 
enplaned at the 36 next largest airports in 2009, the most recent year 
for which these data are available. Some of these largest airports 
also face significant congestion and delay issues. As we recently 
reported, seven large airports were the source of about 80 percent of 
departure delays captured in FAA's Operations Network in 2009. 
[Footnote 10] 

The national airspace system in which these airlines and airports 
operate is a complex, interconnected, and interdependent network of 
systems, procedures, facilities, aircraft, airports, and people that 
must work together to ensure safe and efficient operations. FAA, DOT, 
airlines, and airports all affect the efficiency of national airspace 
system operations. In particular, DOT and FAA set policy and operating 
standards for aircraft and airports. 

As we previously reported, the capacity of the aviation system to meet 
the demand of aviation system users is both variable and subject to a 
number of interrelated factors.[Footnote 11] The capacity of the 
aviation system is affected not only by airports' infrastructure, 
including runways and terminal gates, but also by weather conditions 
and air traffic control that can, at any given time, result in 
disruptions and variation in available airport and system capacity. 
For example, some airports have parallel runways that can be used 
simultaneously in good weather but are too close together for 
simultaneous operations in bad weather. In severe weather, airports 
can close, resulting in aircraft being grounded both at the closed 
airport and at other airports where aircraft cannot depart for the 
closed airport. The number of aircraft that can be safely accommodated 
in a given portion of airspace further affects capacity. If too many 
aircraft are trying to use the same airspace, some may be delayed on 
the ground or en route. For example, delays often occur in the New 
York City area because air traffic is so heavy, with three major 
airports located within 100 miles of each other. Airlines' scheduling 
and business practices can also exacerbate airport congestion and 
delays. For instance, some airline business models rely on tight 
turnaround times between flights, which can increase the likelihood of 
delays for flights scheduled later in the day. Additionally, airlines 
sometimes schedule flights during certain periods to accommodate 
passenger demand without considering an airport's available capacity. 

When flights are disrupted--whether caused by reductions in system 
capacity (such as during bad weather) or by internal factors (such as 
aircraft mechanical problems or crew shortages)--airlines make trade- 
offs between long delays and cancellations, though they generally try 
to avoid canceling flights.[Footnote 12] In doing so, they attempt to 
minimize disruptions to their network and passengers. For example, 
when bad weather reduces airport capacity and fewer flights can take 
off or land, airlines must decide how to ration their traffic. They 
can hold to their schedule, recognizing that some flights may 
experience long delays, or they can cancel some flights to avoid long 
delays for the remaining flights. How airlines manage such trade-offs 
depends on their business models and the circumstances of each 
situation. 

As we recently reported, flight delays and cancellations have declined 
since 2007, largely because airlines have scheduled fewer flights 
during the economic downturn.[Footnote 13] From 2007 through 2010, the 
portion of flights that were delayed--that is, arrived at least 15 
minutes later than scheduled--or were canceled or diverted decreased 
by 6 percentage points, according to DOT data (see figure 1). Indeed, 
cancellations rates also peaked in 2007 at 2.16 percent of all 
flights, before declining to 1.39 percent in 2009 and 1.76 percent in 
2010. Nevertheless, as we previously reported, airports still 
experience and contribute substantial delays to the system.[Footnote 
14] 

Figure 1: Percentages of Delayed, Canceled, and Diverted Arrival 
Flights Systemwide, Calendar Years 2004-2010: 

[Refer to PDF for image: stacked vertical bar graph] 

Year: 2004; 
Percentage of arrival flights that are delayed more than 15 minutes: 
19.95%; 
Percentage of arrival flights that are canceled: 1.79%; 
Percentage of arrival flights that are diverted: 0.19%. 

Year: 2005; 
Percentage of arrival flights that are delayed more than 15 minutes: 
20.52%; 
Percentage of arrival flights that are canceled: 1.88%; 
Percentage of arrival flights that are diverted: 0.2%. 

Year: 2006; 
Percentage of arrival flights that are delayed more than 15 minutes: 
22.61%; 
Percentage of arrival flights that are canceled: 1.71%; 
Percentage of arrival flights that are diverted: 0.23%. 

Year: 2007; 
Percentage of arrival flights that are delayed more than 15 minutes: 
24.18%; 
Percentage of arrival flights that are canceled: 2.16%; 
Percentage of arrival flights that are diverted: 0.23%. 

Year: 2008; 
Percentage of arrival flights that are delayed more than 15 minutes: 
21.74%; 
Percentage of arrival flights that are canceled: 1.96%; 
Percentage of arrival flights that are diverted: 0.25%. 

Year: 2009; 
Percentage of arrival flights that are delayed more than 15 minutes: 
18.88%; 
Percentage of arrival flights that are canceled: 1.39%; 
Percentage of arrival flights that are diverted: 0.24%. 

Year: 2010; 
Percentage of arrival flights that are delayed more than 15 minutes: 
18.21%; 
Percentage of arrival flights that are canceled: 1.76%; 
Percentage of arrival flights that are diverted: 0.24%. 

Source: GAO analysis of DOT data. 

[End of figure] 

In recent decades the airline industry's earnings have been extremely 
volatile. Despite some periods of strong growth and increased 
earnings, airlines have at times suffered such substantial financial 
distress that some have filed for bankruptcy. According to a recent 
FAA-sponsored research study, U.S. passenger airlines lost more than 
$60 billion from 2000 through 2008 on revenues of just more than $1 
trillion.[Footnote 15] An inefficient air transportation system that 
contributes to flight delays and cancellations increases airline costs 
and reduces demand for air travel, compounding these financial 
challenges. 

Airline industry financial pressures have led airlines to change 
certain business practices in order to cut costs and enhance revenue. 
For example, airlines have adjusted their capacity to increase 
passenger load-factors (i.e., the proportion of available seats filled 
with passengers). As a result, a large number of cancellations by an 
airline cannot be absorbed easily into later flights and, 
increasingly, airlines will not rebook passengers on other airlines' 
flights because of the costs involved. Passengers on canceled flights 
can then face long overall trip delays. In addition, for decades 
airlines have sought to reduce the revenue losses associated with 
passengers who do not show up for flights by accepting reservations 
for more passengers than they have seats. Because the number of no-
shows is not entirely predictable, there is an element of risk in 
overbooking flights. If too many reservations are accepted and more 
passengers show up at departure time than the aircraft can carry, the 
airline must deal with the costs and customer service issues that 
arise when some customers are denied boarding. On the other hand, if 
the airline does not accept enough reservations for the flight and the 
number of no-shows is greater than expected, the airline loses revenue 
from empty seats that could otherwise have been occupied and some 
passengers are denied the opportunity to book their first-choice 
flight even though that flight could have accommodated them. DOT has 
long required airlines to solicit and compensate volunteers on 
oversold flights before anyone is bumped involuntarily and has also 
mandated financial compensation for passengers who are involuntarily 
denied boarding because their flights were oversold[Footnote 16].: 

Passenger complaints about delays, cancellations, and denied 
boardings, including complaints about being held in an aircraft for 
many hours while awaiting takeoff, have led Congress to consider 
stronger passenger protections. For instance, after hundreds of 
passengers were stuck in planes on snowbound Detroit runways for more 
than 8 hours in January 1999, both the House of Representatives and 
Senate conducted hearings on airlines' treatment of air travelers and 
considered whether to enact a "passenger bill of rights." The Air 
Transport Association and its member airlines maintained that they 
should have an opportunity to improve their customer service without 
legislation and executed an Airline Customer Service Commitment on 
June 17, 1999, in which each of the member airlines agreed to prepare 
a customer service plan.[Footnote 17] In 2000, AIR-21 mandated a 
review by the DOT Office of Inspector General (IG) of the extent to 
which each airline met all provisions of its customer service plan. 
[Footnote 18] In its 2001 report, the IG found that, overall, airlines 
were making progress toward meeting their plan provisions and that 
their efforts had been a plus for air travelers. However, the IG also 
reported "significant shortfalls in reliable and timely communication 
with passengers by the airlines about flight delays and 
cancellations." Furthermore, the IG found that the airlines had not 
directly addressed the root cause of customer dissatisfaction--flight 
delays and cancellations--and had not indicated how they planned to 
remedy these problems in areas under their control. Other passenger 
rights bills were introduced in Congress in 2001, 2007, 2009, and 
2011.[Footnote 19] These bills were also designed to establish and 
enhance airline passenger protections, and the 2007, 2009, and 2011 
bills explicitly limited tarmac delays to 3 hours. However, the 2001, 
2007, and 2009 bills were not enacted, and the 2011 bill has not yet 
been enacted during this Congress. 

In recent years, DOT has adopted rules to enhance passenger 
protections. First, in 2008, it amended its overbooking rule to 
increase the required compensation for involuntarily denied boarding, 
among other things.[Footnote 20] Second, in late 2009, after a lengthy 
rulemaking and a task force report on long tarmac delays, DOT issued 
its first "Enhancing Airline Passenger Protections" rule.[Footnote 21] 
The final rule, in effect since April 29, 2010, requires certain U.S. 
airlines to develop and implement a contingency plan for lengthy 
tarmac delays, including an assurance that, for domestic flights, 
[Footnote 22] the airline will not allow a tarmac delay to exceed 3 
hours unless the pilot-in-command determines that there is a safety-
related or security-related impediment to deplaning passengers, or 
that air traffic control has advised the pilot-in-command that 
deplaning would significantly disrupt airport operations.[Footnote 23] 
The airlines' contingency plans must also include an assurance that 
adequate food and potable water will be provided no later than 2 hours 
after the aircraft leaves the gate (or touches down, in the case of an 
arrival), unless the pilot-in-command determines that safety or 
security considerations preclude such service. Failure to comply with 
these rules could be considered an unfair or deceptive practice 
[Footnote 24] and may subject the airline to enforcement action and a 
fine of up to $27,500 per violation.[Footnote 25] Furthermore, under 
the rule, the holding out--advertising or operating--of any 
chronically delayed flight is considered an unfair and deceptive 
practice and an unfair method of competition. The rule also requires a 
variety of other actions on the part of airlines to protect and better 
inform passengers. 

In April 2011, DOT issued its second "Enhancing Airline Passenger 
Protections" rule.[Footnote 26] This rule--which partially went into 
effect in August 2011 and will be fully implemented in January 2012-- 
requires airlines, among other things, to reimburse passengers for 
baggage fees if their bags are lost, provide consumers with greater 
compensation for involuntarily denied boarding, and disclose all fees 
for optional services.[Footnote 27] The new rule also expands the 
existing tarmac delay rule to cover all U.S. large-, medium-, small-, 
and nonhub airports as well as foreign airlines' operations at those 
U.S. airports, and establishes a 4-hour time limit on tarmac delays 
for international flights of U.S. and foreign airlines, subject to 
safety, security, and air traffic control exceptions. 

Like the United States, Canada, and EU also have laws, regulations, 
and guidance governing consumer protection for air travelers, 
including airline responsibilities to passengers when flight plans are 
disrupted. U.S., Canadian, and EU airlines generally must adhere to 
the passenger protection requirements of the region from which they 
are departing.[Footnote 28] Airlines in all three regions also have 
contracts of carriage in which they may provide for passenger care, 
compensation, or both in the event of a flight disruption.[Footnote 
29] Thus, when provided for in law or in a contract of carriage, 
[Footnote 30] passengers may be entitled to assistance, compensation, 
or both from their airline when a flight delay, cancellation, or 
denied boarding occurs.[Footnote 31] For example, under certain 
circumstances, some airlines offer food and beverage vouchers during 
flight disruptions. Finally, international standards and agreements 
also govern the rights of airline passengers, but only on 
international flights. Notably, the Montreal Convention, adopted in 
1999 and ratified by the United States in 2003, provides that 
passengers can bring legal action against an airline for damages 
associated with flight delays.[Footnote 32] 

Airports in Rural Communities Have Higher Rates of Delays, 
Cancellations, and Diversions than Larger Communities, but DOT Data 
Provide an Incomplete Picture of These Trends: 

Airports in Rural Communities Have a Higher Rate of Delays, 
Cancellations, and Diversions than Larger Communities: 

The percentages of flights that are canceled or diverted have in 
recent years been higher to and from airports in rural communities 
than large metropolitan communities, according to FlightStats data. 
[Footnote 33] We categorized airports based on the population size of 
their surrounding communities to assess the extent to which flight 
delays, cancellations, and diversions differ by community size. 
[Footnote 34] Our analysis of departure cancellation and diversion 
trends, using FlightStats data for all reported flights, shows that, 
since 2005, flights from airports in rural communities (communities 
with less than 50,000 people) are on average about 3.5 times as likely 
to be canceled or diverted as flights from airports in large 
metropolitan communities.[Footnote 35] For example, in 2010, 
cancellations and diversions accounted for roughly 2 percent of 
flights from large, midsized, and small metropolitan communities, 
compared with nearly 8 percent of flights from airports in rural 
communities (see figure 2).[Footnote 36] Greater cancellation rates 
for flights departing rural airports were matched by higher rates of 
cancellation for flights arriving at rural airports. (See appendix II 
for more information). Such cancellations and diversions can lead to 
long overall delay times for passengers. According to one academic 
study, the overall average delay time for passengers on canceled 
flights is about 5 hours.[Footnote 37] 

Figure 2: Percentage of Canceled or Diverted Departures by Community 
Size in 2010: 

[Refer to PDF for image: stacked vertical bar graph] 

Community size: Large metropolitan; 
Percentage of flights canceled: 1.79%; 
Percentage of flights diverted: 0.16%.  

Community size: Midsized metropolitan; 
Percentage of flights canceled: 2.05%; 
Percentage of flights diverted: 0.21%.  

Community size: Small metropolitan; 
Percentage of flights canceled: 2.37%; 
Percentage of flights diverted: 0.17%.  

Community size: Rural; 
Percentage of flights canceled: 7.01%; 
Percentage of flights diverted: 0.95%.  

Source: GAO analysis of FlightStats data. 

Note: Community sizes are as follows: large metropolitan (greater than 
or equal to 1 million), midsized metropolitan (250,000 to 999,999), 
small metropolitan (50,000 to 249,999), and rural (fewer than 50,000). 
These data reflect the vast majority of scheduled passenger flights. 
In 2010, for example, the data included performance information for 
about 98 percent of U.S. scheduled passenger flights from primary 
airports excluding airports in U.S. territories. 

[End of figure] 

The percentage of delayed arrivals--that is, flights that arrived at 
least 15 minutes late to their destination--has in recent years been 
higher at airports in rural communities than airports in small, 
medium, and large metropolitan sized communities, according to 
FlightStats data, though the difference is not as substantial for 
delays as it is with canceled or diverted flights. As shown in figure 
3, while delays occurred in 19.6 percent of all reported flights 
systemwide in 2010, delays occurred in 21.7 percent of flights to 
airports in rural communities, a 2.1 percentage points or about 11 
percent difference in the occurrence of delay. See appendix II for 
arrival and departure delay trends since 2005. Such delays can lead to 
longer overall trip times for passengers. According to academic 
research, the overall average delay time for passengers on a delayed 
flight is 37 minutes.[Footnote 38] 

Figure 3: Percentage of Delayed Arrivals by Community Size and 
Systemwide in 2010: 

[Refer to PDF for image: combined vertical bar and line graph] 

Community size: Large metropolitan; 
Percentage of delayed arrivals: 19.59%; 
Percentage of delayed arrivals systemwide: 19.64%. 

Community size: Midsized metropolitan; 
Percentage of delayed arrivals: 20.05%; 
Percentage of delayed arrivals systemwide: 19.64%. 

Community size: Small metropolitan; 
Percentage of delayed arrivals: 18.72%; 
Percentage of delayed arrivals systemwide: 19.64%. 

Community size: Rural; 
Percentage of delayed arrivals: 21.65%; 
Percentage of delayed arrivals systemwide: 19.64%. 

Source: GAO analysis of FlightStats data. 

Note: Community sizes are as follows: large metropolitan (greater than 
or equal to 1 million), midsized metropolitan (250,000 to 999,999), 
small metropolitan (50,000 to 249,999), and rural (fewer than 50,000). 
These data reflect the vast majority of scheduled passenger flights. 
In 2010, for example, the data included performance information for 
about 98 percent of U.S. scheduled passenger flights from primary 
airports, excluding airports in U.S. territories. 

[End of figure] 

DOT's Data Provide an Incomplete Picture of Flight Delay, 
Cancellation, and Diversion Trends: 

DOT's data on flight performance do not show similar disparities 
between rural and other airports as do the FlightStats data because 
many flights captured by FlightStats are not required to be reported 
to DOT. As a result, DOT data provides an incomplete picture of delay, 
cancellation, and diversion trends. DOT requires airlines with at 
least 1 percent of total domestic scheduled passenger service revenue 
to report flight performance data for flights they operate to and from 
reportable airports.[Footnote 39] In 2010, 18 airlines reported data, 
which accounted for 22 percent of all commercial airlines, 69 percent 
of all scheduled flights, and 85 percent of all passengers. The 
approximately 31 percent of flights not in DOT's data are scheduled 
flights operated by airlines that are not required to report. Some of 
these flights are those operated by regional airlines for legacy 
airlines, and in general the airlines not required to report to DOT 
are small and tend to provide much of the service to airports in small 
metropolitan and rural communities. Therefore, DOT's data do not 
provide a complete picture of flight performance, especially at 
airports in smaller communities. For example, according to DOT's data 
for 2010, delays, cancellations, and diversions occurred in 19.6 
percent of flights to airports in rural communities and 20.2 percent 
of flights to airports in large metropolitan communities. However, 
FlightStats' more extensive data show a bigger difference by community 
size, with 27.3 percent of flights to airports in rural communities 
delayed, canceled, or diverted, compared with 21.6 percent of flights 
to airports in large metropolitan communities in 2010 (see figure 4). 
[Footnote 40] 

Figure 4: Percentage of Delayed, Canceled, and Diverted Arrivals by 
Community Size in 2010 for DOT and FlightStats Data: 

[Refer to PDF for image: vertical bar graph] 

Community size: Large metropolitan; 
DOT percentage delayed, canceled, and diverted: 20.19%; 
FlightStats percentage delayed, canceled, and diverted: 21.56%. 

Community size: Midsized metropolitan; 
DOT percentage delayed, canceled, and diverted: 20.85%; 
FlightStats percentage delayed, canceled, and diverted: 21.92%. 

Community size: Small metropolitan; 
DOT percentage delayed, canceled, and diverted: 18.71%; 
FlightStats percentage delayed, canceled, and diverted: 20.84%. 

Community size: Rural; 
DOT percentage delayed, canceled, and diverted: 19.63%; 
FlightStats percentage delayed, canceled, and diverted: 27.31%. 

Sources: GAO analysis of DOT and FlightStats data. 

Note: Community sizes are as follows: large metropolitan (greater than 
or equal to 1 million), midsized metropolitan (250,000 to 999,999), 
small metropolitan (50,000 to 249,999), and rural (fewer than 50,000). 
These data reflect the vast majority of scheduled passenger flights. 
In 2010, for example, the data included performance information for 
about 98 percent of U.S. scheduled passenger flights from primary 
airports, excluding airports in U.S. territories. 

[End of figure] 

Our analysis of FlightStats' and DOT's delay and cancellation data 
suggests that airlines not required to report flight performance 
information to DOT have higher delay, cancellation, and diversion 
rates than airlines that are required to report. As figure 4 shows, 
delay, cancellation, and diversion rates are higher, regardless of 
community size, when using FlightStats data, as opposed to DOT data. 
FlightStats data includes a greater percentage of all flights than 
DOT's data, 98 versus 77 percent, and data trends are similar for 
similar flights within each data set. Therefore, airlines not required 
to report to DOT likely account for greater rates of delays, 
cancellations, and diversions. According to FlightStats data, in 2010, 
airlines that were required to report to DOT had lower delay, 
cancellation, and diversion rates on average than the 20 largest 
airlines not required to report to DOT.[Footnote 41] 

This information corroborates what we were told by various 
stakeholders, including airline officials and aviation researchers. 
According to stakeholders that we spoke with, these differences may 
exist for multiple reasons (see figure 5). For example, airlines 
operating from smaller airports may have limitations that affect their 
on-time performance, such as their use of smaller aircraft, which can 
face greater restrictions during certain weather events. As the DOT 
Office of Inspector General has reported, airports in rural 
communities may have higher delay and cancellation rates because the 
airlines serving them may have more limited resources, such as spare 
aircraft and crew, at those airports than at metropolitan airports. 
[Footnote 42] Furthermore, when FAA institutes traffic management 
initiatives to meter air traffic to and from airports, airlines must 
choose which of their flights to delay or cancel. According to 
previous academic research and aviation stakeholders that we spoke 
with, airlines usually prioritize flights by revenue, number of 
passengers, aircraft size, route distance, and competition, or flight 
frequency.[Footnote 43] In cases where marketing airlines control 
operational decisions for their regional partners, the marketing 
airlines may disproportionately delay or cancel flights operated by 
their smaller, regional partners because those flights tend to be 
operated with smaller aircraft with fewer passengers and shorter 
routes with less competition from other airlines. Our analysis of two 
legacy airlines shows that their regional partners generally have 
worse on-time performance. According to FlightStats data, in 2010, two 
large legacy airlines canceled 1.96 percent and 1.51 percent of their 
own flights, compared with 2.46 percent and 2.43 percent of the 
flights regional airlines operated for them. While cancellations to 
smaller communities may inconvenience a relatively small number of 
passengers, they may result in long trip delays if those smaller 
communities have infrequent service. See appendix II for more 
information on sources of delay and cancellations. 

Figure 5: Examples of Sources of Delay by Community Size: 

[Refer to PDF for image: illustrated table] 

Factors that may affect delay: Aircraft type; 
Details: Smaller airplanes (which generally service small airports in 
rural communities) are more likely to be restricted during certain 
weather events. For example, according to the DOT Office of the 
Inspector General, these planes are not allowed to fly over some weather
patterns or land in some wind conditions, which may delay these planes 
or force them to cancel at some airports and not others. 

Factors that may affect delay: Airport size; 
Details: Airports in rural communities are generally smaller and 
therefore may have more air carrier delays because airlines have fewer 
resources available to respond to mechanical and staff issues. 

Factors that may affect delay: Airline economic resources; 
Details: Airline economic decisions may also affect cancellation and 
delay trends. When extenuating circumstances, such as weather or 
congestion, force airlines to reduce the number of flights they can 
operate, airlines must choose which flights to delay or cancel. 
Airline decisions that take into consideration the number of 
passengers affected, access to alternative routings, or other factors 
may affect smaller communities either positively or negatively, 
according to the DOT Office of the Inspector General. 

Factors that may affect delay: FAA traffic management initiatives; 
Details: FAA traffic management initiatives that restrict traffic to
certain airports or geographic areas at certain times in response to 
events such as weather or congestion are more prevalent at larger 
airports. 

Sources: GAO analysis of aviation research and interviews with airline 
officials 

[End of figure] 

DOT has historically not collected flight performance information from 
smaller airlines because of the burden it has perceived would be 
placed on these airlines.[Footnote 44] Without this information, 
though, DOT cannot provide consumers with a complete picture of flight 
performance, particularly at airports in smaller communities or for 
smaller airlines.[Footnote 45] More comprehensive data would provide 
consumers with better information on airlines' performance. Requiring 
airlines with a smaller percentage of the total domestic scheduled 
passenger service revenue, or airlines that operate flights for other 
airlines, to report flight performance information are two ways that 
would enhance DOT's data. According to DOT officials, they have 
considered reducing the reporting threshold from 1 percent of domestic 
scheduled revenue to 0.5 percent to increase the percentage of flights 
captured. This change, they estimate, would require an additional 12 
airlines to report to DOT and increase coverage from about 85 percent 
to more than 96 percent of all passengers. In its December 2009 
passenger protections rule, DOT required airlines that are required to 
report on-time performance data to DOT to include on-time performance 
information on their Web sites for all flights for which their sites 
have schedule information. In doing so, it rejected the concern that 
airline publication of data from smaller code-sharing airlines on 
their Web sites would be overly burdensome, and also noted that flight 
performance information was necessary for consumers to make informed 
decisions when selecting flights. 

New Rule Has Nearly Eliminated Long Tarmac Delays but is Correlated 
with an Increase in the Likelihood of Flight Cancellations: 

The Number of Long Tarmac Delays Has Declined in Recent Years: 

Since 2004, tarmac delays of more than 3 hours peaked in 2007, three 
years before the tarmac delay rule was implemented. The decline prior 
to the imposition of the rule is likely the result of a combination of 
factors, including fewer flights since 2007, runway and other 
improvements at some airports, as well as voluntary limits adopted by 
some airlines on how long their flights can wait on the tarmac. Tarmac 
delays of more than 3 hours, which occur as a plane is taxiing out of 
or in to an airport gate ("taxi-out" or "taxi-in"), have historically 
been relatively uncommon, accounting for less than 0.1 percent of all 
reported flights, according to our analysis of DOT data (see figure 
6).[Footnote 46] The vast majority, about 97 percent, of tarmac delays 
of more than 3 hours occur during taxi-out (departure), rather than 
during taxi-in (arrival). 

Figure 6: Tarmac Delays of More than 3 Hours during Taxi-Out and Taxi- 
In by Year, January 2004-September 2010: 

[Refer to PDF for image: 2 vertical bar graphs] 

Number of tarmac delays: 

Year: 2004; 
Taxi-out: 1,169; 
Taxi-in: 70. 

Year: 2005; 
Taxi-out: 983; 
Taxi-in: 32. 

Year: 2006; 
Taxi-out: 1,220; 
Taxi-in: 58. 

Year: 2007; 
Taxi-out: 1,507; 
Taxi-in: 30. 

Year: 2008; 
Taxi-out: 1,056; 
Taxi-in: 17. 

Year: 2009; 
Taxi-out: 520; 
Taxi-in: 2. 

Year: 2010; 
Taxi-out: 72; 
Taxi-in: 4. 

Source: GAO analysis of DOT data. 

Notes: Beginning in October 2008, DOT required airlines to submit 
tarmac delay statistics for three additional categories: flights that 
are subsequently canceled or diverted or have multiple gate 
departures. For consistency, we have omitted these flights from this 
figure. Our analysis also excluded flights reported to DOT by Atlantic 
Southeast Airlines, Hawaiian Airlines, and Comair because, according 
to DOT, these airlines inconsistently reported gate returns prior to 
October 2008. Specifically, some airlines misreported the gate- 
departure or takeoff time resulting in an incorrect tarmac delay 
calculation. Further, our analysis excluded data for any flights with 
tarmac delays of more than 10 hours since there were errors in the 
reporting of many such flights. Finally, our analysis did not include 
data for international flights. As a result of these exclusions for 
data reliability purposes, this figure likely under-reports tarmac 
delays of more than 3 hours for these years. See appendix IV for more 
information on recent tarmac delays. 

[End of figure] 

The majority of all tarmac delays of more than 3 hours (180 minutes) 
since 2004 are 4 hours (240 minutes) or less (see figure 7). 
Specifically, of the 6,740 tarmac delays of more than 3 hours reported 
from January 2004 through September 2010, almost 83 percent (or 5,579) 
were for 4 hours or less. However, given the length of some of these 
delays and the inconvenience or even hardship they sometimes create 
for passengers, tarmac delays have received widespread media attention 
(see appendix IV for examples of tarmac delays of more than 3 hours 
since October 2008, when DOT began collecting more data on such 
delays).[Footnote 47] 

Figure 7: Total Tarmac Delays of More than 3 Hours (180 minutes) by 
Minutes of Delay, January 2004-September 2010: 

[Refer to PDF for image: pie-chart] 

181 to 240 minutes: 5,579; 
241 to 300 minutes: 967; 
301 to 360 minutes: 153; 
361 minutes or longer: 41. 

Source: GAO analysis of DOT data. 

Notes: Tarmac delay trends, by delay time, are proportionally similar 
across years. As a result, we have combined the data for years 2004 
through September 2010. In addition, the average length of taxi-out 
and taxi-in tarmac delays is similar, as is the proportion of those 
delays that extend beyond 3 hours. Beginning in October 2008, DOT 
required airlines to submit tarmac delay statistics for three 
additional categories: flights that are subsequently canceled or 
diverted or have multiple gate departures. For consistency, we have 
omitted these flights from this figure. Our analysis also excluded 
flights reported to DOT by Atlantic Southeast Airlines, Hawaiian 
Airlines, and Comair because, according to DOT, these airlines 
inconsistently reported gate returns prior to October 2008. 
Specifically, some airlines misreported the gate-departure or takeoff 
time resulting in an incorrect tarmac delay calculation. Further, our 
analysis excluded data for any flights with tarmac delays of more than 
10 hours since there were errors in the reporting of many such 
flights. Finally, our analysis did not include data for international 
flights. As a result of these exclusions for data reliability 
purposes, this figure likely under-reports tarmac delays of more than 
3 hours for these years. See appendix IV for more information on 
recent tarmac delays. 

[End of figure] 

Tarmac delays of more than 3 hours are generally clustered around 
certain weather events, during specific times of the year or day, and 
at specific airports. For example, tarmac delays of more than 3 hours 
most often occur during summer thunderstorms or winter storms, when 
airport departures are halted.[Footnote 48] According to our analysis 
of DOT data from January 2004 through September 2010, almost two-
thirds of all tarmac delays of more than 3 hours occurred from May 
through September. Also, these tarmac delays tend to be clustered on a 
select number of days. According to our analysis of DOT data, almost 
74 percent of tarmac delays of more than 3 hours, from January 2004 
through September 2010, occurred on about 7 percent of the days during 
this time period. For example, on July 23, 2008, 113 flights were 
delayed more than 3 hours on the tarmac across the national airspace 
system during taxi-out.[Footnote 49] Tarmac delays also tend to occur 
in the late afternoon, when summer thunderstorms are most likely, and 
after delays from the morning and early afternoon are compounded. For 
example, since 2004, about half of all tarmac delays of more than 3 
hours occurred between 3:00 p.m. and 6:00 p.m. local time. Tarmac 
delays are also most prevalent at airports that have high rates of 
delays. For example, about 55 percent of tarmac delays of more than 3 
hours since 2004 occurred at just seven particularly congested 
airports.[Footnote 50] See appendix III for more details on these 
trends. 

Tarmac Delays More than 3 Hours Have Been Nearly Eliminated Since DOT 
Implemented Rule: 

DOT instituted new rules in 2010 in response to instances of 
passengers subject to lengthy tarmac delays, among other consumer-
related problems.[Footnote 51] Since these rules took effect in April 
2010, tarmac delays greater than 4 hours have been eliminated, and 
tarmac delays of more than 3 hours nearly eliminated, reducing the 
hardship of long on-board delays for some passengers. As mentioned 
earlier, these new rules require, among other things, that covered 
airlines' contingency plans provide for adequate food and water on all 
flights once a flight has been on the tarmac for 2 hours, except when 
safety or security preclude such services. Additionally, for domestic 
flights, the rule requires that covered airlines should not remain on 
the tarmac for more than 3 hours, with exceptions for safety, 
security, and disruption of airport operations.[Footnote 52] Violation 
of these rules can result in a $27,500 per-violation fine.[Footnote 
53] Since the rule went into effect in late April 2010, tarmac delays 
of more than 3 hours (180 minutes) have been nearly eliminated (see 
figure 8). In the first 12 months since the rule went into effect, 
airlines reported tarmac delays of more than 3 hours for 20 flights, 
compared with 693 over the same period prior to the rule.[Footnote 54] 
Airline consumer groups we spoke with strongly support the tarmac 
delay rule instituted by DOT. 

Figure 8: Total Flights on the Tarmac of More than 1 Hour During Taxi- 
Out, May-September 2009 and 2010: 

[Refer to PDF for image: vertical bar graph] 

Number of flights on the tarmac: 

Time on tarmac: 61-120 minutes; 
May-September 2009: 22,364; 
May-September 2010: 17,763. 

Time on tarmac: 121-180 minutes; 
May-September 2009: 2,391; 
May-September 2010: 1,257. 

Time on tarmac: 181-240 minutes; 
May-September 2009: 351; 
May-September 2010: 9. 

Time on tarmac: 241 minutes or more; 
May-September 2009: 62; 
May-September 2010: 0. 

Source: GAO analysis of DOT data. 

Note: This information is based on DOT data for all reporting airlines 
systemwide. 

[End of figure] 

A small number of flights have sat on the tarmac for more than 3 hours 
since the rule went into effect, including four that resulted in 
violations where airlines were warned. In the first 12 months after 
the implementation of the rule, DOT identified 20 incidents where 
flights were delayed on the tarmac more than 3 hours and determined 
that 11 of these did not violate the tarmac rule, 4 were violations 
which resulted in a warning to the airline, and 5 which are still 
under investigation (see appendix IV for a list of these flights). 
[Footnote 55] Twelve of these 20 flights were canceled and none sat on 
the tarmac for more than 4 hours, according to DOT data.[Footnote 56] 
DOT has not defined, in the regulation or elsewhere, what constitutes 
a violation of the rule that warrants a fine, though DOT enforcement 
officials told us that when determining whether to assess a fine, as 
well as how much to assess, they consider, among other things, the 
nature of the violation, the harm caused to passengers, whether the 
delay was preventable, and the size and financial condition of the 
airline. According to these officials, airlines are operating under 
the assumption that a fine could be assessed at $27,500 per passenger 
because DOT's current authority allows for penalties at up to $27,500 
"per violation," a phrase which is not defined in statute or 
regulation.[Footnote 57] 

The Number of Flight Cancellations Have Increased Since DOT 
Implemented Rule: 

Overall, the number of flight cancellations have increased since the 
tarmac delay rule was implemented, according to DOT data, though these 
cancellations cannot be directly attributed to the rule.[Footnote 58] 
Our analysis of cancellation trends examined flights during the last 
two summers, May through September, 2009 and 2010 because they 
represent equivalent periods of time before (2009) and after (2010) 
the implementation of the rule. Furthermore, as noted previously, the 
summer historically accounts for the majority of tarmac delays. While 
the number of scheduled flights was similar in these time periods, 
total cancellations increased by 5,068 (see table 1).[Footnote 59] 
Total cancellations as a percentage of all flights increased from 1 
percent in 2009 to 1.2 percent in 2010, a 20 percent increase in the 
rate of cancellations. Cancellation rates also increased for the 
subset of flights that left the gate and then sat on the tarmac. 
[Footnote 60] For example, the percentage of flights that were 
canceled after sitting on the tarmac for between 2 and 3 hours (121 to 
180 minutes) increased from 6.19 percent in 2009 to 17.34 percent in 
2010. As a result of challenges rebooking passengers, such 
cancellations can lead to long overall delay times. 

Table 1: Cancellations by Stage of Flight, May-September 2009 and 2010: 

Canceled before taxi-out; 
2009, Total cancellations: 27,161; 
2009, Percent canceled of all flights: 0.98%; 
2010, Total cancellations: 31,985; 
2010, Percent canceled of all flights: 1.16%. 

Time on tarmac: 1-60 minutes; 
2009, Total flights: 2,711,384; 
2009, Total cancellations: 824; 
2009, Percent canceled: 0.03%; 
2010, Total flights: 2,709,532; 
2010, Total cancellations: 926; 
2010, Percent canceled: 0.03%. 

Time on tarmac: 61-120 minutes; 
2009, Total flights: 22,364; 
2009, Total cancellations: 259; 
2009, Percent canceled: 1.16%; 
2010, Total flights: 17,763; 
2010, Total cancellations: 396; 
2010, Percent canceled: 2.23%. 

Time on tarmac: 121-180 minutes; 
2009, Total flights: 2,391; 
2009, Total cancellations: 148; 
2009, Percent canceled: 6.19%; 
2010, Total flights: 1,257; 
2010, Total cancellations: 218; 
2010, Percent canceled: 17.34%. 

Time on tarmac: 181-240 minutes; 
2009, Total flights: 351; 
2009, Total cancellations: 57; 
2009, Percent canceled: 16.24%; 
2010, Total flights: 9; 
2010, Total cancellations: 7; 
2010, Percent canceled: 77.78%. 

Time on tarmac: 241 or more minutes; 
2009, Total flights: 62; 
2009, Total cancellations: 15; 
2009, Percent canceled: 24.19%; 
2010, Total flights: 0; 
2010, Total cancellations: 0; 
2010, Percent canceled: n/a. 

All flights: 
2009, Total flights: 2,763,713; 
2009, Total cancellations: 28,464; 
2009, Percent canceled: 1.0%; 
2010, Total flights: 2,760,546; 
2010, Total cancellations: 33,532; 
2010, Percent canceled: 1.2%. 

Source: GAO analysis of DOT data. 

Note: This information is based on DOT data for all reporting airlines 
systemwide. 

[End of table] 

According to DOT, although cancellations have increased since the 
tarmac delay rule was implemented, few, if any, additional 
cancellations can be attributed to the introduction of the tarmac 
delay rule. DOT's analysis is limited, though, because it includes 
only a portion of all flights, considers the total number of 
cancellations instead of the rate of cancellation, and does not 
control for other factors that can affect cancellations. In a March 
2011 analysis of flight cancellations from 2009 and 2010, DOT found 
that, for the period from May through October, the number of flights 
canceled after sitting on the tarmac for 2 hours or more increased by 
six flights from 2009 to 2010.[Footnote 61] However, as indicated in 
table 1, the number of flights that remained on the tarmac for more 
than 2 hours (121 or more minutes) declined by more than half--2,804 
to 1,266--from 2009 to 2010. As a result, the rate of cancellation 
increased from 2009 to 2010. DOT also did not control for the other 
factors, such as weather, that can affect an airline's decision to 
cancel a flight. When such factors are not controlled for, the 
observed changes in cancellations, and any associated costs, cannot be 
estimated. A complete consideration of the costs and benefits of the 
tarmac delay rule cannot be conducted without, at a minimum, 
controlling for these factors. Such a consideration is important 
because, according to the Office of Management and Budget, a 
fundamental indicator of a publicly acceptable rule is one in which 
public benefits exceed public costs. 

Airlines Maintain They Have Changed Decision Making in Response to 
Tarmac Delay Rule: 

Airline and other aviation industry stakeholders that we spoke with 
maintained that the tarmac delay rule has changed how airlines balance 
the trade-off between the extent to which flights are delayed and 
canceled, and that this change has made flight cancellations more 
likely. In particular, these officials told us airlines are more often 
taking actions to avoid potential DOT fines, including returning 
flights to the gate after taxi-out and, because of crew hour limits, 
limited gate availability, or the severity in the underlying cause of 
delay, some of these flights may then be canceled. Furthermore, when 
flights are delayed on the tarmac, airline officials told us they are 
now deciding sooner than they did in the past whether to taxi back in 
to the gate. A majority of the U.S. airline officials we spoke with 
said that, once a flight is delayed on the tarmac, communications 
between airline officials and air traffic control officials on how to 
handle the delay, such as whether to wait or return to the gate now 
starts after about an hour (see figure 9). According to airline 
officials we spoke with, uncertain taxi times for take off and the 
potential for million-dollar fines have made early decision making 
necessary because it may take a significant amount of time for a 
flight to return to the gate, if necessary. Additionally, within 2 
hours, airlines must provide food and water. Airline officials also 
told us that when flights have been on the tarmac for 2 hours, the 
pilots begin executing a plan for either takeoff or a return to the 
gate within the hour. According to one airline official, this plan 
must then be carried out unless they are told by air traffic control 
that takeoff is imminent. Officials from one airline told us that 
their decision to return to the gate is sometimes put into action 
before the flight has been on the tarmac for 2 hours. As a result, 
airlines are returning more flights to the gate prior to takeoff. Our 
analysis of DOT data found that the number of flights returning to the 
gate after waiting on the tarmac for at least an hour has increased by 
almost 9 percent from May through September 2009 to May through 
September 2010, although it is not possible to definitively attribute 
these changes solely to the tarmac delay rule. 

Figure 9: Domestic Airlines' Decision-Making Timeline for Flights 
Experiencing a Taxi-Out Delay on the Airport Tarmac: 

[Refer to PDF for image: illustrated table] 

Prior to departure: 
If tarmac delay or other disruption, such as weather delay, is likely, 
flight may be canceled. 

0–1 hour after leaving gate: 
* Plane leaves gate and proceeds to ramp area then queues for take-off; 
* Delay begins if weather, congestion, or other factors prevents take- 
off or increases length of queue. 

1–2 hours: 
* After an hour on the tarmac, communication may begin between airline 
officials, pilots, and FAA’s air traffic controllers at the airport; 
* Pilot and airline officials will develop a strategy for either 
returning to the gate or taking off by the 3 hour mark. 

2–3 hours: 
* By the 2 hour mark, the airline is required to provide passengers with
food and water; 
* Pilots will execute the airline’s strategy to avoid a continued 
tarmac delay and potential fine. 

After 3 hours: Flight will have:
* taken off; 
* canceled; 
* returned to the gate and permitted passengers to deplane prior to 
continuing the flight to its original destination; or; 
* remained on the tarmac, making it possibly subject to DOT fine. 

Sources: GAO analysis of tarmac delay rule and aviation stakeholder 
interviews. 

Note: The decision-making timeline described in this figure is a 
general representation of airline decision-making processes based on 
academic studies and interviews with airline officials. The processes 
and decisions may vary between airlines based on their business 
practices and the specific circumstances. 

[End of figure] 

In addition to stating that the tarmac delay rule is altering their 
decision making during a tarmac delay, airlines maintain that the rule 
has increased the likelihood that they will cancel a flight before it 
ever leaves the gate. For instance, airline officials told us that 
they are precanceling more flights prior to the scheduled departure 
time when long tarmac delays are possible, such as during severe 
weather, than they did in the past. According to an official from one 
airline, its precancellations have increased by 10 percent since late 
April 2010, when the rule went into effect. When canceling a flight 
before passengers have boarded the plane, airlines have more control 
over where they position crew and aircraft to resume normal operations 
the following day. According to one major airline, precanceling also 
benefits flight crews and airport employees because it gives airlines, 
airports, and passengers greater flexibility in rescheduling flights, 
work, and personal activities.[Footnote 62] 

Our Analysis Finds That the Tarmac Delay Rule is Correlated with an 
Increased Likelihood of Flight Cancellations: 

Since a variety of factors in addition to the tarmac delay rule may be 
correlated with airline cancellation decisions, we developed logistic 
regression models that control for several factors that are likely to 
be associated with these decisions in order to measure the likely 
effect of the tarmac delay rule.[Footnote 63] We used two models to 
analyze cancellations. In the first (the tarmac-cancellation model), 
we assessed the likelihood of cancellation for all flights that taxi-
out from the gate. In the second (the gate-cancellation model), we 
assessed the likelihood of cancellation for flights before they leave 
the gate.[Footnote 64] Our analysis examined flights during the last 
two summers (May through September 2009 and 2010) because DOT began 
collecting more extensive data on tarmac delays that is necessary for 
this analysis in October 2008 and, historically, the majority of 
tarmac delays occur in the summer.[Footnote 65] Both models control 
for several factors that are likely to influence airlines' decisions 
about whether to cancel flights, including weather at the origin and 
destination airport, airline characteristics, and specific details of 
individual flights. Nevertheless, other factors related to 
cancellations may not have been fully controlled for. Additionally, 
since we used a variable indicating the year as a proxy for the 
implementation of the rule in late April 2010, other general changes 
in the environment across these two years which affect how airlines 
decide whether to cancel a flight may not be fully reflected in our 
model. See appendix V for a detailed discussion of the model 
structure, a full list of independent variables, and our full results. 

Model Results: 

Results from the tarmac-cancellation model suggest that the 
implementation of the tarmac delay rule is associated with a greater 
likelihood of cancellation for flights that taxi-out onto the tarmac. 
Furthermore, our results suggest that the greater likelihood of 
cancellation increases with the time a plane stays on the tarmac. As 
shown in table 2, we grouped flights into hour-long intervals, and for 
each group the likelihood of cancellation has increased since the rule 
went into effect. This correlation of the rule's implementation with 
increased cancellations appears consistent with what airlines have 
told us has happened. 

Table 2: Percent Difference in Likelihood of Flight Cancellation after 
Implementation of Tarmac Delay Rule: 

Time on tarmac: Before taxi-out (at gate); 
Increased likelihood of cancellation in 2010 compared with 2009: 24 
percent more likely. 

Time on tarmac: 1-60 minutes; 
Increased likelihood of cancellation in 2010 compared with 2009: 31 
percent more likely. 

Time on tarmac: 61-120 minutes; 
Increased likelihood of cancellation in 2010 compared with 2009: More 
than twice as likely (214 percent). 

Time on tarmac: 121-180 minutes; 
Increased likelihood of cancellation in 2010 compared with 2009: More 
than 3 times as likely (359 percent). 

Source: GAO analysis of DOT data. 

Notes: 

1. These results are based on analysis of all flights, operated by DOT 
reporting airlines, to and from 70 of the FAA's Aviation System 
Performance Metrics 77 airports in the United States and Puerto Rico. 

2. The percentage differences in the likelihood of cancellation 
presented here are based on odds ratios calculated from our models. In 
particular, the figure for cancellations before taxi-out is from our 
gate-cancellation model, which estimates the effect of different 
factors (including the implementation of the tarmac delay rule) on the 
odds of flights being canceled at the gate. The figures for 
cancellations after taxi-out are from our tarmac-cancellation model, 
which estimates the effect of different factors (including the 
implementation of the tarmac delay rule) on the odds of flights being 
canceled after taxi-out on to the tarmac. All figures reported in the 
table are statistically significant at the 1 percent level. Our tarmac-
cancellation model also showed a large, statistically significant 
increase in the likelihood of cancellation in 2010 compared with 2009 
for flights on the tarmac for more than 3 hours, but we excluded that 
information from this table because of the very small number of 
flights that experienced such long tarmac delays in 2010. 

[End of table] 

Results from the gate-cancellation model also indicate that the tarmac 
delay rule is associated with a higher rate of flight cancellation. In 
particular, when the model controlled for other factors that may be 
associated with an airline's decision to cancel a flight, the 
likelihood of a gate cancellation was 24 percent higher during May 
through September 2010 than it was for the same months in 2009 (see 
table 2). The gate-cancellation model also controlled for the same 
factors as the tarmac model except for minutes on the tarmac. For both 
models, the tarmac delay rule as well as the other factors we included 
generally had the expected, and statistically significant, association 
with cancellations.[Footnote 66] 

EU Requirements Provide More Comprehensive Passenger Protections, but 
May Also Increase Costs for Airlines and Passengers: 

Passenger Protections Requirements Are More Extensive in the EU than 
in the United States or Canada: 

Passenger protections requirements for flight delays, cancellations, 
and denied boarding are overall more extensive in the EU than they are 
in the United States or Canada. While all three regions have enhanced 
passenger protections in recent years, EU care and compensation 
guarantees are generally more extensive than those in the United 
States or Canada. (Table 3 summarizes what airlines are required to 
provide passengers for flight delays, cancellations, and denied 
boardings in the three regions.) In April 2011, U.S. DOT further 
enhanced its airline passenger protections by, among other things, 
increasing financial compensation in the event of an involuntary 
denied boarding. The Canadian Minister of Transport, Infrastructure 
and Communities launched "Flight Rights Canada" in September 2008 to 
increase air passenger's awareness of their rights, which includes a 
voluntary "Code of Conduct of Canada's Airlines" which, among other 
things, recommends Canadian airlines adopt specific provisions related 
to flight disruptions in their contracts of carriage.[Footnote 67] In 
the EU, a regulation enacted in 2004 entitles passengers to care and 
compensation, under specific circumstances, for all three types of 
disruptions.[Footnote 68] Officials from the European Commission 
(Commission) told us that these rules harmonized levels of customer 
service across all EU member states and airlines, ensuring that 
passengers can expect to be cared for and compensated if their flight 
is canceled or seriously delayed or if the passenger is denied 
boarding. Before the current regulation was put into place, according 
to these European officials, some airlines were increasingly 
overbooking flights, while providing little care or compensation to 
those inconvenienced passengers who were denied boarding. The 
officials said that the goal of the regulation was not to punish 
airlines for delays or cancellations, or even necessarily reduce the 
number of disruptions, but rather to make passengers "whole" when 
flights are disrupted. 

Table 3: Comparison of Governmental Requirements in the United States, 
Canada, and the EU of Benefits Provided to Passengers by Airlines 
during Flight Disruptions: 

Flight disruption: Delay; 
United States: No federal requirements for care or compensation[A]; 
Canada: No requirements for care or compensation; 
EU: 
* Passengers on flights delayed 2 or more hours from departure 
(dependent on flight distance) entitled to care, including, meals, 
refreshments, communication services, and, in certain cases, hotel 
accommodations[B]; 
* Passengers on flights delayed more than 5 hours, entitled to 
reimbursement in part or in full, dependent upon circumstances,[C] and 
a return flight to the first point of departure, at the earliest 
opportunity if they decide to pursue their journey.[D] 

Flight disruption: Cancellation; 
United States: Refund for unused portion of ticket[E]; 
Canada: No requirements for care or compensation; 
EU: Passenger care: 
* Passengers may be entitled to care, such as meals, refreshments, 
communication services, and, in certain cases, hotel accommodations[F]; 
* Passengers entitled to the choice between rerouting or 
reimbursement[G]; 
Passenger compensation:[H] 
* €250 for flights 1,500 kilometers (km)[I] or less; 
* €400 for all intra-community flights more than 1,500 km and all 
other flights between 1,500 km and 3,500 km; 
* €600 for all other flights; 
* May be reduced by 50% if rerouted to destination within certain time 
frames[J]. 

Flight disruption: Denied boarding; 
United States: Passenger compensation:[K] 
* 200% of the fare (up to $650) if transported to the final 
destination (or first stopover, if one) more than 1 hour but less than 
2 hours (or more than 1 hour but less than 4 for international 
flights) of scheduled arrival; 
* 400% of the fare (up to $1,300) if transported to the final 
destination (or first stopover, if one) 2 hours or more (or 4 hours or 
more for international flights) after the planned arrival time of the 
original flight[L]; 
Canada: No requirements for care or compensation; 
EU: Passenger care: 
* Passenger entitled to care, including, meals, refreshments, 
communication services, and, in certain cases, hotel accommodations[M]; 
Passenger compensation:[N] 
* €250 for flights 1,500 km or less; 
* €400 for all intra-community flights more than 1,500 km and all 
other flights between 1,500 km and 3,500 km; 
* €600 for all other flights; 
* May be reduced by 50 percent if rerouted to destination within 
certain time frames[O]. 

Source: GAO analysis of laws and regulations. 

[A] According to DOT, passengers who experience an extensive delay are 
entitled to the same benefits as those who experience a cancellation, 
however, DOT has not defined what constitutes an "extensive" delay. In 
instances of tarmac delays, adequate food and potable water must be 
provided no later than 2 hours after the aircraft leaves the gate (or 
touches down, in the case of an arrival). 

[B] Passengers will be entitled to hotel accommodations if the 
reasonable expected time of departure is at least the day after the 
time of departure previously announced. Regulation (EC) 261/2004, art. 
9, 2004 O.J. (L 46/1). See also Id., art. 6(1). But see, infra, C-402/ 
07 and C-432/07, Sturgeon v. Condor Flugdienst GmbH Böck, Lepuschitz 
v. Air France SA, 2009 E.C.R. I-10923. 

[C] Regulation (EC) 261/2004, art. 6(1)(iii), 2004 O.J. (L 46/1). See 
also Id., art. 8(1)(a). 

[D] Id., art. 6(1)(iii). See also Id., art. 8(1)(a). 

[E] According to DOT, airlines do not owe refunds to passengers who 
accept and travel alternate routes to their destinations. 

[F] Regulation (EC) 261/2004, art. 5(1)(b), 2004 O.J. (L 46/1). See 
also Id., art. 9. 

[G] Id., articles 5(1)(a), 8. See also Id., art. 8. 

[H] Id., article 5(1)(c). See also Id., art. 7(1). 

[I] In determining distance, the basis shall be the last destination 
at which the denial of boarding or cancellation will delay the 
passenger's arrival after the scheduled time. Regulation (EC) 
261/2004, art. 7(1), 2004 O.J. (L 46/1). 

[J] Id., art. 7(2). 

[K] 14 C.F.R. § 250.5. On April 25, 2011, DOT issued its final rule on 
Enhancing Air Passenger Protections, which, as of August, 23, 2011, 
increased the denied boarding compensation limits to what is listed 
above, implemented an automatic inflation adjuster for minimum denied 
boarding compensation limits every two years, and clarified the 
application of the rule and requirements imposed on airlines in this 
regard, among other things. 76 Fed. Reg. 23110 (Apr. 25, 2011). 

[L] Pasengers are not entitled to compensation if the airline offers 
alternate transportation that is planned to arrive at the passenger's 
destination or first stopover not later than 1 hour after the planned 
arrival time of the passenger's original flight. 14 C.F.R. § 250.5. 

[M] Regulation (EC) 261/2004, art. 4(3), 2004 O.J. (L 46/1). See also 
Id., art. 9. 

[N] Id., art. 4(3). See also Id., art. 7(1). 

[O] Id., art. 7(2). 

[End of table] 

In the event of a flight delay, the EU regulation requires that 
airlines offer passengers care and, under certain circumstances, the 
option of reimbursement or a return flight to the first point of 
departure, while there are no U.S. and Canadian requirements with 
similar levels of care or compensation.[Footnote 69] Under EU 
regulation, when a flight is delayed at least 2, but less than 5 hours 
(depending on the distance of the flight), airlines are required to 
provide passengers with certain types of care, including meals and 
communication services, and if the delay requires an overnight stay 
passengers must be offered hotel accommodations and transportation 
between the airport and hotel.[Footnote 70] Furthermore, if the delay 
is at least 5 hours, passengers must also be offered reimbursement for 
the unused portion of their ticket (and for the part of the journey 
already made if the flight no longer serves its original purpose) and, 
if necessary, a return flight to the point of departure.[Footnote 71] 
They must also be given written notice of the rules for care and 
compensation.[Footnote 72] By comparison, passengers on delayed 
flights in the United States and Canada are not entitled to care or 
compensation by law.[Footnote 73] 

In the EU, when a flight is canceled, the EU regulation requires that 
passengers receive care in certain circumstances, compensation, and 
the option of being rerouted or reimbursed (with a return flight to 
the point of departure), while passengers in the United States and 
Canada do not have such extensive rights. Passengers on canceled 
flights covered by the EU regulation are entitled to the same rights 
as those passengers on delayed flights (as described previously) and, 
additionally must be offered the choice between being 
rerouted[Footnote 74] or reimbursed for part or all of their ticket, 
depending on the circumstances along with a return flight to the first 
point of departure at the earliest opportunity.[Footnote 75] In 
addition, passengers on such flights are entitled to financial 
compensation, the amount of which depends on the length of the 
canceled flight and may be reduced by 50 percent if the passenger is 
rerouted, under certain circumstances.[Footnote 76] An airline may be 
exempt from the obligation to pay compensation if it can prove the 
cancellation was caused by an extraordinary circumstance that could 
not have been avoided even if all reasonable measures had been taken. 
[Footnote 77] At the time a flight is canceled, the airline must 
provide passengers written notice of the rules for compensation and 
assistance.[Footnote 78] By contrast, U.S. rules do not require care 
and compensation in the event of a cancellation, but do, require 
airlines to offer passengers a refund if they do not wish to accept 
and travel alternative routes to their destinations.[Footnote 79] In 
Canada, passengers are not entitled to care or compensation in the 
event of a cancellation, nor is there a specific requirement that an 
airline refund a passenger their ticket price, in whole or in part. 
[Footnote 80] 

If a passenger is involuntarily denied boarding--generally because an 
airline has oversold seats on a flight and cannot find enough 
volunteers willing to take another flight--the passenger may be 
entitled to benefits, depending on the region. Passengers on flights 
covered by the EU regulation have a right to care and financial 
compensation. Comparatively, passengers covered under U.S. regulations 
are entitled to financial compensation and passengers in Canada are 
entitled to neither care nor compensation except as provided under 
their contracts of carriage.[Footnote 81] To limit the number of 
passengers who are involuntarily denied boarding when a flight is 
oversold, airlines in the United States and the EU are required to 
first request volunteers to relinquish their confirmed space in 
exchange for benefits, such as credit for future travel, before 
selecting passengers for denied boarding.[Footnote 82] When selecting 
passengers for denied boarding, U.S. airlines are required to use 
boarding priority rules that are in compliance with DOT regulations. 
[Footnote 83] Under both U.S. and EU requirements, those passengers 
selected for denied boarding must be offered financial compensation. 
[Footnote 84] Passengers in the EU also are guaranteed the same care 
offered to passengers whose flights are delayed or canceled and must 
also be offered the option of reimbursement, in whole or in part, 
dependent upon the circumstances, and a return flight to the first 
point of departure or rerouting the final destination.[Footnote 85] In 
both regions, airlines must notify passengers in writing of their 
rights.[Footnote 86] 

Some airlines in the United States and Canada, as described earlier, 
voluntarily include provisions in their contracts of carriage for care 
and compensation beyond what is legally required for delays, 
cancellations, and denied boarding. These provisions are enforceable 
as a legal contract between the airline and the ticket holder. The 
airlines we spoke with in the EU do not include any additional care or 
compensation beyond the EU requirements discussed previously and the 
EU regulation does not require airlines to include those requirements 
in their contracts of carriage. We examined the contracts of the seven 
largest airlines in the United States and found that five of these 
airlines may, in certain circumstances, provide certain types of care, 
such as meal vouchers and free phone calls, for delays and 
cancellations that extend beyond a certain time (see table 4). Certain 
airlines also state in their contracts of carriage that they must also 
provide hotel accommodations and ground transportation, under certain 
circumstances, when an overnight stay is required. The circumstances 
under which airlines provide these amenities vary and may depend on a 
number of factors, such as the cause, length, and timing of the flight 
disruption. All four of Canada's major airlines have added passenger 
protections for delays, cancellations, and denied boarding in response 
to the 2008 federal government initiative mentioned above, according 
to airline officials in Canada. Although airlines are not required to 
adhere to passenger protection provisions outlined in the initiative's 
Code of Conduct, because all four of Canada's major airlines have 
added its provisions to their contracts of carriage, these become part 
of the binding contract between the airline and the passenger. 
[Footnote 87] As a result, these airlines now guarantee in their 
contracts of carriage that they will provide passengers with a meal 
voucher if a flight delay exceeds 4 hours, as well as hotel 
accommodations and ground transportation if a flight delay exceeds 8 
hours and requires an overnight stay. If a flight is canceled or a 
passenger is denied boarding, the airlines will rebook passengers or 
refund the unused portion of the ticket.[Footnote 88] Flight Rights 
Canada's Code of Conduct does not make the airline responsible for 
acts of nature or the acts of third parties. 

Table 4: Comparison of Contract of Benefits That May be Provided Under 
Domestic Carriage Provisions for Flight Delays and Cancellations for 
Selected U.S. Airlines, as of June 2011: 

Airline: Alaska Airlines; 
Options for transporting passengers: 
Rebook on next available flight offered by the airline: [Check]; 
Rebook on a flight offered by another airline: [Check]; 
Amenities provided to passengers: 
Meals and/or snacks: [Empty]; 
Hotel accommodation and/or ground transportation: [Check]; 
Phone calls: [Check]; 
Credit for future travel: [Check][A]. 

Airline: American Airlines; 
Options for transporting passengers: 
Rebook on next available flight offered by the airline: [Check]; 
Rebook on a flight offered by another airline: [Check]; 
Amenities provided to passengers: 
Meals and/or snacks: [Empty]; 
Hotel accommodation and/or ground transportation: [Check][B]; 
Phone calls: [Empty]; 
Credit for future travel: [Empty]. 

Airline: Delta Air Lines; 
Options for transporting passengers: 
Rebook on next available flight offered by the airline: [Check]; 
Rebook on a flight offered by another airline: [Check]; 
Amenities provided to passengers: 
Meals and/or snacks: [Check]; 
Hotel accommodation and/or ground transportation: [Check]; 
Phone calls: [Empty]; 
Credit for future travel: [Empty]. 

Airline: JetBlue Airways; 
Options for transporting passengers: 
Rebook on next available flight offered by the airline: [Check]; 
Rebook on a flight offered by another airline: [Empty]; 
Amenities provided to passengers: 
Meals and/or snacks: [Check]; 
Hotel accommodation and/or ground transportation: [Check]; 
Phone calls: [Empty]; 
Credit for future travel: [Check][A]. 

Airline: Southwest Airlines; 
Options for transporting passengers: 
Rebook on next available flight offered by the airline: [Check]; 
Rebook on a flight offered by another airline: [Empty]; 
Amenities provided to passengers: 
Meals and/or snacks: [Empty]; 
Hotel accommodation and/or ground transportation: [Empty]; 
Phone calls: [Empty]; 
Credit for future travel: [Empty]. 

Airline: United Airlines; 
Options for transporting passengers: 
Rebook on next available flight offered by the airline: [Check]; 
Rebook on a flight offered by another airline: [Check]; 
Amenities provided to passengers: 
Meals and/or snacks: [Empty]; 
Hotel accommodation and/or ground transportation: [Check][B]; 
Phone calls: [Empty]; 
Credit for future travel: [Empty]. 

Airline: US Airways; 
Options for transporting passengers: 
Rebook on next available flight offered by the airline: [Check]; 
Rebook on a flight offered by another airline: [Check]; 
Amenities provided to passengers: 
Meals and/or snacks: [Empty]; 
Hotel accommodation and/or ground transportation: [Empty]; 
Phone calls: [Empty]; 
Credit for future travel: [Empty]. 

Source: GAO analysis of airline contracts of carriage as of June 2011. 

Note: We selected these airlines from the 10 largest U.S. airlines 
using FAA's data on airline available seat miles from the last 12 
months for which data were available. Available seat miles are 
calculated by multiplying aircraft miles flown in inter-airport 
flights by the number of seats available for revenue passenger use on 
those flights. Although AirTran Airways and Continental Airlines were 
among the 10 largest U.S. airlines, we did not include them in this 
analysis because they have recently merged with Southwest Airlines and 
United Airways, respectively, and therefore we expect that these 
airlines will refer to the contract of carriage of their purchasing 
airline. We also did not include SkyWest because it follows the 
policies of the airline partner that tickets its flights. SkyWest 
partners with AirTran Airways, Delta Air Lines, and United Airlines. 
This table does not include provisions that are required by law to be 
provided in the event of a lengthy tarmac delay, and also excludes 
provisions for refunds. The options for transportation and amenities 
offered to passengers vary by airline and by circumstances. For 
example, some airlines offer these services to passengers only when 
the airline is the cause of the flight disruption and airlines differ 
by the amount of time a delay and cancellation must exceed before 
providing passengers with amenities. 

[A] For flight delays that exceed 2 hours, Alaska Airlines offers 
passengers 2,000 Mileage Plan Bonus Miles. JetBlue offers passengers a 
$50 credit for future travel when its flights are canceled due to a 
controllable irregularity within 4 hours of the scheduled departure 
time. JetBlue passengers are also entitled to credit when their flight 
is delayed due to a controllable irregularity: $25 if the delay is 
greater than 1 hour but less than 2 hours, $50 if the delay is greater 
than 2 hours but less than 4 hours, credit equal to the one-way trip 
fare if the delay is greater than 5 hours but less than 6 hours, and 
credit equal to the roundtrip fare if the delay is greater than 6 
hours. 

[B] American Airlines provides hotel accommodation if the delay or 
cancellation was caused by events within the airline's control and 
United Airlines provides hotel accommodations in the event of a flight 
diversion. 

[End of table] 

Passenger Protections May Increase Costs for Airlines and Passengers: 

Care and compensation requirements provide protections and benefits 
for passengers whose flights are disrupted, but they also increase 
costs to airlines and could increase passengers' fares. Airline 
officials we spoke with in the EU and the United States maintained 
that passenger protections increase their costs, though they did not 
provide documentation of specific cost increases because they consider 
the information to be confidential.[Footnote 89] While data from 
airlines on these costs are unavailable, a February 2010 study of the 
EU passenger protection requirements noted that airlines the study 
authors spoke with reported the cost of compliance for EU airlines 
ranges from 0.1 to 0.5 percent of airlines' annual revenue.[Footnote 
90] However, officials from one European airline, as well as officials 
from an airline association, maintained that airlines' cost of 
compliance exceeds this estimate. Increases in required compensation 
for passengers denied boarding have also increased costs for both U.S. 
and EU airlines, according to airline officials we spoke with. In the 
United States, officials with some U.S. airlines told us that 
complying with the requirements to better inform passengers about 
routinely delayed and canceled flights and to post information such as 
flight on-time performance data on airline Web sites costs hundreds of 
thousands of dollars. Officials with one of these airlines estimated 
that airline personnel spent about 3 months adding the information at 
the airline's Web site. Some airlines in the United States and the EU 
told us that compliance costs such as these can lead to higher fares. 
However, it is very difficult to isolate the impact of compliance on 
fares because they are set based on demand in competitive markets as 
well as other factors.[Footnote 91] 

Passenger protections can create financial burdens on airlines for 
major events outside their control. For example, as noted above, 
airlines subject to EU regulations are required to provide certain 
care in the event of a delay or cancellation, regardless of whether 
the disruption was within the airline's control. These regulations 
require an airline to provide passengers with food, lodging, and other 
care, dependent on the circumstances, during short-term disruptions in 
travel plans. However, when major disruptions to the airspace system 
occur, this requirement can obligate airlines to provide passengers 
with lodging and other care for extended periods of time at great 
cost.[Footnote 92] Such a situation occurred in 2010 when the European 
air transport industry was significantly affected by the consequences 
of the Eyjafjallajökull volcanic eruption in Iceland. The volcano, 
which erupted on April 14, 2010, created a cloud of volcanic ash that 
drifted through large sections of European airspace. Volcanic ash 
contains substances that may harm aircraft, so national authorities 
decided to close affected airspace. As a result, more than 100,000 
flights were canceled and millions of passengers were unable to fly. 
In many cases, the passengers were stranded in a foreign country 
without any immediate possibility to go back home. Representatives of 
one EU airline told us that when the eruption occurred, they booked 
more than 100,000 hotel rooms for their scheduled passengers and 
eventually chartered aircraft to get passengers to their destinations. 
The airline's representatives estimated that the incident cost the 
airline about $4.5 million. Major disruptions generally result from 
unsafe flying conditions. According to airline officials in both the 
United States and EU, the possibility of large monetary claims as a 
result of such incidents could pressure airlines to operate in 
conditions they would otherwise deem unsafe for flight in order to 
avoid high costs, but according to Commission officials there are no 
available data on the existence or extent of this issue. 

While increasing the compensation for denied boarding will increase 
airline's costs if airlines don't change their booking policies, 
reducing overbooking reduces revenues because fewer seats can be sold, 
according to airlines officials we interviewed. Overbooking is a 
revenue-producing strategy for many airlines, without which some would 
raise fares to offset their losses.[Footnote 93] Additionally, airline 
officials said that reductions in overbooking could also limit the 
flexibility of passengers when choosing flights, as seat availability 
would be reduced and airline policies governing how and when 
passengers change their flights could become more restrictive. 
However, we found little evidence that increases in denied boarding 
compensation in the United States resulted in reduced overbooking. 
According to airline officials we spoke with, the 2008 compensation 
increase in the United States was not large enough to cause airlines 
to reduce their overbooking of flights.[Footnote 94] Additionally, 
from 2004 through 2010, the number of voluntary denied boardings in 
the United States was less than 0.1 percent of all U.S. passengers 
boarded annually, while the number of involuntary denied boardings 
rose slightly but remained rare in relation to the total number of 
U.S. passengers, at 0.01 percent of all U.S. passengers (see figure 
9). In contrast, EU denied boarding compensation, though in some cases 
less than U.S. levels, has been significant enough to cause at least 
two EU airlines to reduce overbooking of flights, according to 
officials from these airlines.[Footnote 95] According to these 
officials, this reduction in overbooking has adversely affected 
consumers through higher average ticket costs designed to offset the 
increased number of unused seats on each flight. However, data showing 
whether any such reductions in overbooking have caused EU airlines to 
increase their fares are not available. 

Figure 10: Voluntary and Involuntary Denied Boardings in the United 
States as a Percentage of Total Passengers, Calendar Years 2004-2010: 

[Refer to PDF for image: multiple line graph] 

Year: 2004; 
Percent of passengers voluntarily denied boarding: 0.092%; 
Percent of passengers involuntarily denied boarding: 0.006%. 

Year: 2005; 
Percent of passengers voluntarily denied boarding: 0.073%; 
Percent of passengers involuntarily denied boarding: 0.006%. 

Year: 2006; 
Percent of passengers voluntarily denied boarding: 0.077%; 
Percent of passengers involuntarily denied boarding: 0.007%. 

Year: 2007; 
Percent of passengers voluntarily denied boarding: 0.074%; 
Percent of passengers involuntarily denied boarding: 0.008%. 

Year: 2008; 
Percent of passengers voluntarily denied boarding: 0.077%; 
Percent of passengers involuntarily denied boarding: 0.008%. 

Year: 2009; 
Percent of passengers voluntarily denied boarding: 0.091%; 
Percent of passengers involuntarily denied boarding: 0.009%. 

Year: 2010; 
Percent of passengers voluntarily denied boarding: 0.087%; 
Percent of passengers involuntarily denied boarding: 0.008%. 

Source: GAO analysis of DOT data. 

Note: This figure reflects data from airlines with at least 1 percent 
of total domestic scheduled passenger service revenue. 

[End of figure] 

Enforcing Passenger Protections Can Create Challenges: 

Extensive passenger protections, while providing benefits and 
guarantees to passengers, can create challenges for the government 
entities responsible for enforcing the requirements and for passengers 
in obtaining benefits due to them. These challenges include 
difficulties enforcing unclear requirements and ineffective passenger 
complaint processes. Such challenges can limit the potential for the 
requirements to mitigate hardships for airline passengers. 

Government enforcement bodies in each region are responsible for 
ensuring that airlines comply with their region's requirements. DOT 
and the Canadian Transportation Agency (CTA) serve as the enforcement 
bodies for the United States and Canada, respectively. In the EU, each 
of its 27 member states, and other countries that joined the EU 
aviation market (such as Iceland, Norway, and Switzerland), 
establishes its own body responsible for enforcing the EU regulation, 
which is typically the agency responsible for aviation oversight. 
These enforcement bodies use similar activities to monitor airline 
compliance, including investigating passenger complaints and issuing 
penalties against airlines for noncompliance. Enforcement bodies in 
each region receive passenger complaints or information (for example, 
through a media report) about a possible violation of passenger 
protections and decide whether to investigate.[Footnote 96] DOT 
officials told us they will investigate any case alleging a violation 
of a DOT rule, but will generally only pursue an enforcement action 
against airlines if they discover a pattern or practice of violations 
or the incident is particularly egregious. CTA officials and an 
enforcement body official from one EU member state told us they 
investigate and may pursue enforcement actions against an airline 
based on an individual's complaint.[Footnote 97] If officials 
determine that an airline has violated passenger protections, they may 
fine the airline, depending on the region or the member state. 
[Footnote 98] In addition to conducting investigations based on 
passenger complaints, enforcement bodies in each region initiate 
investigations. For example, DOT officials told us they routinely 
investigate each major airline and their investigations have resulted 
in the collection of fines.[Footnote 99] In two EU member states, 
officials from the enforcement bodies told us they visit airports to 
see if airlines are displaying required information about passenger 
protections, but have not issued fines. 

Lack of Clarity in Regulations and Confusion in Application: 

The first challenge to the effective application of passenger 
protections arises when there is a lack of clarity in regulations. In 
the EU, where passenger protection regulations are more extensive than 
in the United States or Canada, officials from the Commission told us 
that different interpretations of these regulations by enforcement 
bodies in different member states have made it challenging to ensure 
successful implementation of the regulation. A 2010 study for the 
Commission about the impact of the EU passenger protection regulation 
found that more needs to be done to ensure that passengers' rights are 
properly protected.[Footnote 100] In particular, the study noted that 
in some areas the rights granted by the regulation can lead to 
different understandings. The Commission also recently reported that 
"the novelty of some provisions of the Regulation has led to different 
interpretations, and thus varied application, among airlines and 
national enforcement authorities, rendering it difficult for 
passengers and stakeholders to understand the scope and limits of the 
rights set out."[Footnote 101] Stakeholders told us, for example, that 
the following two provisions were unclear and confusing to implement, 
respectively: 

* Unclear definition of extraordinary circumstances. According to some 
airlines, airline associations, and consumer groups we spoke with in 
the EU, the definition of this term--which refers to situations in 
which airlines are exempt from the passenger compensation requirement 
when a flight is canceled--has left room for confusion.[Footnote 102] 
A recent ruling by the European Court of Justice (ECJ) provided some 
clarification for enforcement bodies when it ruled that technical 
issues, such as an airplane malfunction, may constitute an 
extraordinary circumstance only when these issues stem from events 
outside the normal activities of the airline and are beyond its 
control.[Footnote 103] Even so, some enforcement bodies are 
interpreting this ruling differently. For example, officials from one 
enforcement body told us that even if a technical issue is routine, 
they may still consider it an extraordinary circumstance if they 
believe the safety risks were too great, whereas other enforcement 
bodies in the EU have interpreted the ECJ's ruling more strictly. 

Additionally, some stakeholders that we spoke with told us that the 
extraordinary circumstance provision in the regulation should be 
revised to restrict the amount of assistance an airline must provide 
to passengers or to identify an extensive list of scenarios under 
which the airline would be exempt from the passenger compensation 
requirement. For example, officials from an airline and an airline 
association told us that they believe the regulation should be amended 
to exempt airlines from paying for weeks of hotel accommodations and 
food (not just compensation) in response to major disruptions, such as 
the Eyjafjallajökull volcanic eruption. In a recent report, the 
Commision stated this incident illustrated the structural limits of 
the regulation and that the "proportionality of some current measures, 
like the unlimited liability regarding the right to care under major 
natural disaster, may merit assessment." 

* Confusion over definition of delay. Uncertainty about when 
compensation is required for delays and cancellations has also created 
enforcement challenges. In the EU, a November 2009 ruling of the ECJ 
specified that passengers whose flights are delayed more than 3 hours 
experience the same inconvenience as those whose flights are canceled 
and therefore both should be entitled to the same financial 
compensation payments from airlines.[Footnote 104] This ruling created 
confusion in member states and within the industry as to when to 
compensate passengers who have been delayed. Airline and some airline 
association officials told us that this ruling contradicts the text of 
the regulation, which, requires reimbursement (in part or in full), 
not compensation, in the event of a delay of more than 5 hours. In the 
United Kingdom (UK), according to Commission officials, the 
International Air Transport Association, among others, filed a suit in 
the UK Court of Justice against the UK's enforcement body's policy to 
compensate passengers in line with the ECJ ruling.[Footnote 105] An 
official from the UK's enforcement body told us that the UK Court of 
Justice submitted questions of law stemming from this case to the ECJ 
and until the ECJ responds with further clarification, the enforcement 
body has suspended all investigations into complaints on the topic. 
[Footnote 106] Uncertainties over these provisions may make it 
difficult for airlines and passengers to know when an airline must 
compensate its passengers. 

The challenges arising from the lack of clarity pertaining to 
passenger protection regulations, such as the confusion about the 
definition of delay, can be exacerbated when the EU requirement is 
applied unevenly across jurisdictions. For instance, the enforcement 
of EU regulations has been complicated because member states have 
flexibility in structuring their enforcement to account for 
differences in their national laws and policies.[Footnote 107] As a 
result, enforcement bodies in the Netherlands and Germany, for 
example, use different sanction strategies for ensuring that the 
airlines comply with the regulation, resulting in varying types and 
amounts of penalties for airlines. In particular, the types of 
sanctions and amounts of sanctions these enforcement bodies can impose 
differ because of laws and policies specific to their member state. 
Officials from the Netherlands's enforcement body told us they can 
impose only reparatory sanctions, which prevents them from collecting 
a fine if the airline makes amends with the passenger, while the 
enforcement body in Germany can issue repressive sanctions, which can 
be imposed regardless of whether the airline makes amends with the 
passenger.[Footnote 108] The amount of a sanction also differs between 
the two member states. For example, the Dutch enforcement officials 
told us that there is no set amount, but it must be reasonable and 
proportionate to the severity of the violation, while in Germany, 
officials from the enforcement body told us that the amount of a 
sanction is based on the seriousness of the complaint. Different 
national laws affect the circumstances in which sanctions can be 
issued. For example, the German officials told us that German law 
prohibits them from considering ECJ decisions, such as the ruling that 
passengers who are delayed more than 3 hours should receive the same 
compensation as those whose flights are canceled, and therefore the 
German enforcement body is not using the same standards as other 
enforcement bodies to sanction airlines. 

Ineffective Passenger Complaint Process: 

The second challenge to the application of passenger protections 
arises when there is a lack of an effective passenger complaint 
process. The enforcement processes of the EU, as well as those of the 
United States and Canada, demonstrate challenges passengers can face 
obtaining benefits due to them. When passengers in the United States, 
Canada, or the EU do not receive benefits to which they believe they 
are entitled, they can submit a complaint to any or all of three 
entities: the airline, the national enforcement body, or the court 
system (see figure 11). However, according to government officials, 
passengers in the United States and EU can receive financial 
compensation only through the airline or the court.[Footnote 109] The 
enforcement bodies in these regions cannot award passenger 
compensation because their authority does not extend to enforcing 
payment by the airlines.[Footnote 110] The 2010 study for the 
Commission of the regulation reported inconsistent implementation and 
enforcement of the regulation across enforcement bodies and airlines. 
[Footnote 111] According to the study, airlines and consumer groups 
reported that there are a number of difficulties associated with 
passengers in the EU seeking compensation in a court, including the 
costs, time burden, availability of small claims courts, and limits on 
amounts awarded.[Footnote 112] In the EU, according to Commission 
officials, passengers may pay for legal assistance when pursuing 
compensation in the courts from a variety of sources, such as from a 
consumer protection organization. In some member states, passengers 
can also use the commercial claim service EU Claim, but passengers 
must pay for these services with a percentage of what they are 
awarded.[Footnote 113] Officials from one consumer group told us that 
when barriers are imposed on passengers claiming their benefits for 
violations of their rights, airlines may not comply with applicable 
requirements. Furthermore, despite a number of EU government-sponsored 
campaigns to inform passengers of their rights, several EU 
stakeholders told us passengers may still not be aware of their rights 
and therefore may not submit complaints if they believe their rights 
have been violated.[Footnote 114] Additionally, officials from two 
consumer protection groups in the EU told us that some passengers may 
be confused about their rights under the EU regulation and some 
airlines may use that confusion to their advantage.[Footnote 115] 

Figure 11: Airline Passenger Complaint Process in the United States, 
Canada, and the EU: 

[Refer to PDF for image: process map] 

Passenger submits complaint: 

1) An airline passenger who wants to submit a complaint about a flight 
disruption in the United States, Canada, or the EU has three options. 
They can submit the complaint to any or all of these venues; however, 
passengers in the United States and the EU can only receive 
compensation through the airline or court.[A] 

Airline: 

2) Airline provides passenger with satisfactory response, which may 
include compensation. 

3) Airline provides passenger with an unsatisfactory response 
(passenger can submit a complaint to an enforcement body or in court). 

Enforcement Body: (Enforcement bodies include U.S. Department of 
Transportation, Canadian Transportation Agency or relevant member 
state National Enforcement Body in the EU) 

4) Based on approach (either looking for trends of individual 
complaints or investigating each complaint) enforcement body may 
decide to investigate an airline. 

5) Enforcement body finds airline is at fault, which may result in a 
penalty for the airline, but not compensation for passengers 
(individuals can submit a claim in court or return to the airline for 
compensation), except in Canada[A]; or: 

6) Enforcement body finds airline is not at fault. 

Court: 

7) Judge rules in favor of passenger and may award compensation; or: 

8) Judge rules in favor of airline, no compensation awarded. 

Source: GAO analysis. 

[A] In Canada, if the enforcement body finds that an airline has 
failed to apply the provisions of its contract of carriage, it can 
require the airline to apply the relevant provisions and also award 
out-of-pocket expenses that were incurred by the passenger, according 
to officials from the CTA. They may also order appropriate corrective 
measures pursuant to regulation. Air Transportation Regulations SOR/88-
58, Part V, Div. II, § 113.1(a) (Can). According to DOT, it may obtain 
compensation for consumers through settlements of potential violations 
with airlines and may also insert such provisions into a consent order. 

[End of figure] 

Conclusions: 

Flight disruptions remain costly for passengers, airlines, and the 
economy. DOT has responded by enacting regulations to protect 
passengers in the event of tarmac delays and has enhanced involuntary 
denied boarding protections. DOT's tarmac delay rule has eliminated 
delays greater than 4 hours and nearly eliminated tarmac delays of 
more than 3 hours, thereby benefiting tens of thousands of passengers. 
Increased compensation for involuntary denied boardings provides for 
passengers in the event they are bumped from their reserved flight. 

Although DOT's rules have benefited some passengers, DOT's current 
flight performance data may not fully inform consumers of airlines' 
quality of service as intended. By collecting data only from the 
largest airlines, DOT does not obtain and therefore cannot provide 
consumers with a complete picture of flight performance, particularly 
at airports in rural communities or among smaller airlines. Accurate 
flight performance information is necessary for consumers to make 
informed decisions when purchasing airline tickets. 

Additional information and analysis are also needed to fully 
understand the effects of the tarmac delay rule on passengers. Since 
the rule went into effect, tarmac delays of more than 3 hours have 
been nearly eliminated, with no delays of more than 4 hours, reducing 
the hardship for numerous passengers. However, as our analysis has 
shown, the rule appears to be associated with an increased number of 
cancellations for thousands of additional passengers--far more than 
DOT initially predicted--including some who might not have experienced 
a tarmac delay. Though it is difficult to know how passengers might 
choose between a long tarmac delay and a cancellation, and what costs 
and burdens their choices would entail, determining the net benefit to 
airline passengers resulting from the rule and assessing whether there 
is a causal relationship between the rule and any changes in flight 
cancellations will be critical to passengers and airlines. 
Additionally, our analysis could only include data from the first 
summer of the rule's implementation, so using data through the summer 
of 2011 may yield useful information for policymakers. In determining 
the impact of the rule, it is important to include both the positive 
effects of reducing long on-board delays and the negative effects of 
flight cancellations on passengers. Increases in cancellations may be 
at least partly due to airlines' assumptions about the significant 
enforcement penalties that could result from a violation of the rule. 
Although DOT could issue guidance on their penalty structure, it has 
chosen not to in order to maintain flexibility under their current 
authority. 

Recommendations for Executive Action: 

To enhance aviation consumers' decision-making, we recommend that the 
Secretary of Transportation take the following action: 

* Collect and publicize more comprehensive on-time performance data to 
ensure that information on most flights, to airports of all sizes, is 
included in the Bureau of Transportation Statistics' database. DOT 
could accomplish this by, for example, requiring airlines with a 
smaller percentage of the total domestic scheduled passenger service 
revenue, or airlines that operate flights for other airlines, to 
report flight performance information. 

To enhance DOT's understanding of the impact of tarmac delays and 
flight cancellations, we recommend that the Secretary of 
Transportation take the following action: 

* Fully assess the impact of the tarmac delay rule, including the 
relationship between the rule and any increase in cancellations and 
how they effect passengers and, if warranted, refine the rule's 
requirements and implementation to maximize passenger welfare and 
system efficiency. 

Agency Comments and Our Evaluation: 

We provided a copy of the draft report to DOT for review and comment. 
Senior officials at DOT, including the DOT assistant general counsel 
for aviation enforcement proceedings, provided general comments in an 
e-mail representing DOT's views on the benefits of the tarmac delay 
rule, but did not provide written comments on the recommendations. In 
its general comments, DOT stated that, in its view, available data 
demonstrate that the tarmac delay rule provided effective consumer 
protection for airline passengers. DOT officials believe that the rule 
made clear to airlines that, whatever the rationale, it is not 
acceptable to leave passengers in aircraft stranded on the ground for 
hours on end. Specifically, DOT officials cited data that demonstrate 
the rule's effectiveness in preventing extended tarmac delays, 
including the elimination of tarmac delays in excess of 4 hours, which 
dropped from 105 flights to zero for the year ending April 2011, 
completely eliminating these most egregious of delays. Officials also 
highlighted the 98 percent drop in 3-hour delays, from 693 flights to 
20, during the same period. DOT officials believe that these results 
demonstrate the positive impact of the tarmac rule, and that without 
it, far more passengers would have been subject to these extended 
delays. In response to DOT's general comments, we made changes to the 
report to better clarify our findings. 

DOT officials said that the information in our report, in their view, 
further demonstrates that airlines have gotten the basic message of 
the rule and that it has been effective at putting consumers first 
when it comes to avoiding lengthy tarmac delays. They cited our 
discussion of actions airlines are taking to avoid tarmac rule 
violations, including acting more quickly to address delayed flights 
and moving more quickly back to gates, affording passengers the 
freedom to access the amenities of air terminals. They were also 
pleased to see our finding that air carriers are working to comply 
with DOT requirements to provide food and water to passengers delayed 
on the tarmac for extended periods of time. 

Finally, DOT reinforced its commitment to monitor the effects of the 
tarmac delay rule to ensure it is achieving intended outcomes and to 
address any significant unintended outcomes. DOT initially focused on 
comparing the number of flights with 2-hour tarmac delays that are 
eventually canceled because in its view this was the best measure of 
the effect on cancellations from the rule. According to DOT, they 
recently selected a contractor to conduct a comprehensive independent 
review and analysis of the impact of the tarmac delay rule now that a 
full year of data is available. DOT believes that, at minimum, one 
year of data is necessary to assess the rule's effects. DOT's review 
will consider on-time performance, cancellations, benefits to 
consumers, and other relevant information covering the period back to 
2000, to assess the rule's impact on flight delays, cancellations, and 
consumers. DOT also provided technical comments, which were 
incorporated as appropriate. 

As agreed with your offices, unless you publicly announce the contents 
of this report earlier, we plan no further distribution until 7 days 
from the report date. At that time, we will send copies to interested 
congressional committees and the Secretary of Transportation. In 
addition, this report will be available at no charge on GAO's Web site 
at [hyperlink, http://www.gao.gov]. 

If you or your staff have any questions about this report, please 
contact me at (202) 512-2834 or flemings@gao.gov. Contact points for 
our Offices of Congressional Relations and Public Affairs may be found 
on the last page of this report. Key contributors to this report are 
listed in appendix VI. 

Signed by: 

Susan Fleming: 
Director, Physical Infrastructure: 

[End of section] 

Appendix I: Objectives, Scope, and Methodology: 

In this report, we examined how (1) trends in and reasons for flight 
delays and cancellations in the United States differ for smaller and 
larger communities; (2) the Department of Transportation's (DOT) 
tarmac delay rule has affected passengers and airlines; and (3) 
requirements and practices for protecting passengers from flight 
delays, cancellations, and denied boardings in the United States, 
Canada, and the European Union (EU) have affected passengers and 
airlines. 

To identify and compare the trends in and reasons for flight delays 
and cancellations in different-sized U.S. communities, we examined 
trends at airports designated as primary in fiscal year 2009.[Footnote 
116] From this group of 367 airports, we excluded the 12 primary 
airports in U.S. territories because they operate in different 
operational environments than other U.S. airports. We then categorized 
the 355 airports by the size of their surrounding community. We used 
geographic information system data on the airports' location and 
surrounding population. Airports were mapped by the county they are 
located in and grouped into one of four categories based on 
population: 1,000,000 or greater (large metropolitan), 250,000 to 
999,999 (midsized metropolitan), 50,000 to 249,999 (small 
metropolitan), and less than 50,000 (rural). This approach controls 
for the fact that some small or medium airports--generally secondary 
airports such as Hobby Airport in Houston--are actually in large 
metropolitan regions. Using these categories, 78 airports were in 
large metropolitan communities, 100 were in midsized metropolitan 
communities, 122 were in small metropolitan communities, and 55 were 
in rural communities. 

To analyze flight delay, cancellation, and diversion trends for these 
different airport community size categories, we first obtained data 
from DOT. These data were drawn from the Airline Service Quality 
Performance System (ASQP), which includes information about flight 
delays, cancellations, and diversions. ASQP data are based on 
information filed by airlines each month with DOT's Bureau of 
Transportation Statistics (Office of Airline Information).[Footnote 
117] Airlines with 1 percent or more of total domestic scheduled 
passenger service revenue are required to report data for their 
flights involving any airport in the 48 contiguous states that account 
for one percent or more of domestic scheduled service passenger 
enplanements.[Footnote 118] We then compared the percentage of flights 
that were delayed, canceled, and diverted by community size, by year. 

Since DOT does not require all airlines to report on-time performance 
information, we also purchased data from FlightStats, a private data 
source from Conducive Technology that records flight performance 
information for nearly all airlines and airports. We then conducted 
the same analysis of delay, cancellation, and diversion trends by 
airport community size as we did with ASQP data. We also verified DOT 
and FlightStats data as comparable for similar categories of flights. 

ASQP and FlightStats did not have data for all 355 primary airports 
subject to our examination, because some airports may not have been 
considered primary in other years of our analysis (very small airports 
may drop below or rise above the 10,000 enplanements threshold year to 
year). Furthermore, some airports may have more than 10,000 
enplanements annually but generally not be commercial-service 
airports. For instance, some military airports may have commercial 
flights diverted to them on occasion. As a result, our analysis of the 
year 2010, for example, included data for 281 airports using ASQP data 
and for 344 airports using FlightStats data. Using our community size 
categories, 76 airports were in large metropolitan communities, 99 
were in midsized metropolitan communities, 117 were in small 
metropolitan communities, and 52 were in rural communities when using 
FlightStats data. 

We also examined trends in sources of delay and cancellation, based on 
DOT's ASQP data as previously described, and compared these trends by 
airport community size. FlightStats does not record the sources or 
reasons for delays or cancellations. 

To assess the reliability of ASQP and FlightStats data, we reviewed 
documentation related to both data sources, and interviewed 
knowledgeable officials at DOT and Conducive Technology about the 
data. We also compared data for the same categories of flights in both 
DOT and FlightStats databases, where possible, and found that they 
were similar. After excluding certain ASQP flight records for our 
analysis of tarmac delay trends, we determined that both ASQP and 
FlightStats data were sufficiently reliable for the purposes of this 
report.[Footnote 119] 

To better understand the reasons for any differing trends in and 
sources of flight delays and cancellations, we reviewed a DOT Office 
of Inspector General report and interviewed aviation industry experts, 
consumer groups, industry associations, and representatives of three 
U.S. legacy airlines and three low-cost airlines. For the U.S. 
airlines, we selected three legacy airlines that served more than two- 
thirds of all legacy airline passengers from 2004 through June 2010 
and three low-cost airlines that served more than 80 percent of all 
low-cost airline passengers from 2004 through June 2010. These six 
airlines served about half of all passengers enplaned on U.S. airlines 
from 2004 through June 2010. See table 5 for a list of aviation 
industry stakeholders, including airlines, interviewed for this report. 

Table 5: U.S. Stakeholders Interviewed: 

Government agencies: 
Department of Transportation: 
* Federal Aviation Administration; 
* Bureau of Transportation Statistics; 
* Office of the Assistant General Counsel for Aviation Enforcement & 
Proceedings; 
* Office of the Assistant General Counsel for International Law. 

Academics and consultants: 
Peter Belobaba, Massachusetts Institute of Technology;
Amy Cohn, University of Michigan;
Mark Hansen, University of California, Berkeley;
Darryl Jenkins, ACG Aviation Consulting Group, LLC;
Joshua Marks, Marks Aviation, LLC;
Lance Sherry, George Mason University. 

Consumer groups: 
American Society of Travel Agents;
Association for Airline Passenger Rights;
Business Travel Coalition;
Consumer Travel Alliance;
Consumers Union;
FlyersRights. 

Industry associations: 
Air Carrier Association of America;
Air Transport Association;
International Air Transport Association;
Regional Airline Association. 

U.S. legacy airlines: 
American Airlines;
Delta Air Lines;
United Airlines. 

U.S. low-cost airlines: 
JetBlue Airlines;
Southwest Airlines;
Spirit Airlines. 

Source: GAO. 

[End of table] 

To assess how DOT's tarmac delay rule has affected passengers and 
airlines, we first examined DOT data on tarmac delay and cancellation 
trends since 2004. In order to identify the frequency of tarmac delays 
over time, we used DOT's ASQP data to identify all flights with tarmac 
delays greater than 3 hours from January 2004 through September 2010. 
[Footnote 120] We then analyzed these flights by year; month; time of 
day; and type of tarmac delay, such as taxi-in and taxi-out delays 
(see appendix III for more information on these trends since 2004). 

To better understand the effect of the tarmac delay rule on the 
likelihood of flight cancellations, we assessed cancellations in two 
contexts. In the first, we assessed the odds of a flight being 
canceled after it leaves the gate. In the second, we assessed the odds 
of a flight being canceled before it leaves the gate. In order to 
isolate the effect of the tarmac delay rule, we analyzed flight data 
using models that controlled for a variety of factors that can affect 
an airline's decision to cancel a flight. Specifically, we used 
logistic regression models to estimate the impact of the tarmac delay 
rule on cancellations. Using these models, we were able to control for 
other factors that may affect the likelihood of a cancellation, 
including weather at the origin and destination airport, airport and 
airline characteristics, and specific details of individual flights. 
Disruptive weather is a major cause of cancellations, so by including 
variables in our model for severe weather events, we were better able 
to isolate the rule's correlation with cancellations. Further, the 
size of the particular airport, as well as the size and business 
practices of airlines, influence cancellation decisions, so we 
controlled for certain characteristics of airports and airlines. (See 
appendix V for more details on our models.) To verify the strength of 
our model, we discussed the models' design and preliminary results 
with aviation experts Professor Mark Hansen of the University of 
California and Professor Lance Sherry of George Mason University. We 
also spoke with representatives of U.S. airlines, industry 
associations, consumer groups, and DOT about the impact of the tarmac 
delay rule, including changes to airline practices. 

Finally, to determine how the requirements and practices for 
protecting passengers from flight delays, cancellations, and denied 
boardings in the United States, Canada, and the EU have affected 
passengers and airlines, we examined the laws, regulations, 
international agreements, and voluntary commitments governing 
passenger protections in the three regions. In particular, we reviewed 
applicable DOT regulations, Regulation (EC) 261/2004, and relevant 
provisions of Canada's Air Transportation Regulations and the Montreal 
Convention. Additionally, we examined government guidance and 
proposals for additional passenger protections, including the Flight 
Rights Canada Initiative, European Commission guidance for enforcement 
bodies, and Canada's proposed Air Passenger's Bill of Rights. To 
describe voluntary passenger protections offered by airlines, we 
reviewed the contracts of carriage for nine largest U.S. airlines 
based on recent Federal Aviation Administration (FAA) data on the 
number of available seat miles. We also spoke with airline officials 
from three airlines in Canada and officials from three European 
airlines. To further examine the affect that passenger protection 
regulations have had on airlines and passengers, we interviewed 
airline, industry association, consumer group, and government 
officials throughout all three regions. We also assessed DOT data on 
denied boardings from 2004 through 2010.[Footnote 121] To document how 
regions enforce passenger protection requirements differently, we 
visited and spoke with stakeholders in Canada and in the EU, which 
were selected based on stakeholder comments and a review of a recent 
EC study on the implementation of the EU regulation. In the EU, we 
selected The Netherlands and Germany because each has a large aviation 
market as well as active and effective enforcement practices, but 
which employ different strategies. See tables 6 and 7 for a list of 
stakeholders we met with in Canada and the EU. 

Table 6: Canadian Stakeholders Interviewed: 

Airlines: 
Air Canada;
Air Transat;
WestJet. 

Consumer groups:
Consumer Association of Canada. 

Government agencies:
Canadian Transportation Agency;
NavCanada;
Transport Canada. 

Industry association:
Canadian Airports Council. 

Source: GAO. 

[End of table] 

Table 7: European Stakeholders Interviewed: 

Airlines: 
EasyJet;
KLM;
Lufthansa. 

Consumer groups:
Consumentenbond (Netherlands):
Federation of German Consumer Organisations. 

Government agencies:
EC, Directorate-General for Mobility and Transport;
Germany, Federal Ministry of Food, Agriculture and Consumer Protection;
Germany, Federal Ministry of Transport, Building and Urban Affairs;
Germany, Luftfahrt-Bundesamt;
The Netherlands, Ministry of Transport, Inspectorate for Transport, 
Public Works and Water Management;
United Kingdom, Civil Aviation Authority. 

Industry associations:
Association of European Airlines;
European Low Fares Airline Association;
European Regions Airline Association;
German Airline Federation. 

Source: GAO. 

[End of table] 

[End of section] 

Appendix II: Delay, Cancellation, and Diversion Trends: 

This appendix provides additional information and illustrations of 
flight delay, cancellation, and diversion trends from 2005 to 2010, 
based on our analysis of FlightStats data. It also provides 
information on airline-reported sources of delays and cancellations, 
based on our analysis of DOT data. 

Figure 12: Percentage of Departure Flights Canceled and Diverted by 
Community Size, Calendar Years 2005-2010: 

[Refer to PDF for image: multiple line graph] 

Percentage of departure flights that are diverted or canceled: 

Year: 2005; 
Large metropolitan: 1.57%; 
Midsized metropolitan: 1.85%; 
Small metropolitan: 2.24%; 
Rural: 4.16%. 

Year: 2006; 
Large metropolitan: 1.58%; 
Midsized metropolitan: 1.9%; 
Small metropolitan: 2.29%; 
Rural: 6.25%. 

Year: 2007; 
Large metropolitan: 2.18%; 
Midsized metropolitan: 2.53%; 
Small metropolitan: 2.7%; 
Rural: 6.43%. 

Year: 2008; 
Large metropolitan: 2.03%; 
Midsized metropolitan: 2.58%; 
Small metropolitan: 3.31%; 
Rural: 6.94%. 

Year: 2009; 
Large metropolitan: 1.51%; 
Midsized metropolitan: 2.14%; 
Small metropolitan: 2.6%; 
Rural: 6.24%. 

Year: 2010; 
Large metropolitan: 1.94%; 
Midsized metropolitan: 2.26%; 
Small metropolitan: 2.54%; 
Rural: 7.96%. 

Source: GAO analysis of FlightStats data. 

[End of figure] 

Figure 13: Percentage of Arrival Flights Canceled and Diverted by 
Community Size, Calendar Years 2005-2010: 

[Refer to PDF for image: multiple line graph] 

Percentage of arrivals that are diverted or canceled: 

Year: 2005; 
Large metropolitan: 1.58%; 
Midsized metropolitan: 1.66%; 
Small metropolitan: 2.1%; 
Rural: 3.79%. 

Year: 2006; 
Large metropolitan: 1.61%; 
Midsized metropolitan: 1.65%; 
Small metropolitan: 2.01%; 
Rural: 4.72%. 

Year: 2007; 
Large metropolitan: 2.17%; 
Midsized metropolitan: 2.25%; 
Small metropolitan: 2.7%; 
Rural: 4.75%. 

Year: 2008; 
Large metropolitan: 2.18%; 
Midsized metropolitan: 2.27%; 
Small metropolitan: 2.93%; 
Rural: 9.11%. 

Year: 2009; 
Large metropolitan: 1.58%; 
Midsized metropolitan: 1.7%; 
Small metropolitan: 2.01%; 
Rural: 4.18%. 

Year: 2010; 
Large metropolitan: 1.97%; 
Midsized metropolitan: 1.87%; 
Small metropolitan: 2.11%; 
Rural: 5.65%. 

Source: GAO analysis of FlightStats data. 

[End of figure] 

Figure 14: Percentage of Delayed Departure Flights by Community Size, 
Calendar Years 2006-2010: 

[Refer to PDF for image: multiple line graph] 

Percentage of departures: 

Year: 2006; 
Large metropolitan: 13.61%; 
Midsized metropolitan: 11.72%; 
Small metropolitan: 11.16%; 
Rural: 13.16%. 

Year: 2007; 
Large metropolitan: 16.51%; 
Midsized metropolitan: 13.45%; 
Small metropolitan: 13.16%; 
Rural: 14.09%. 

Year: 2008; 
Large metropolitan: 13.29%; 
Midsized metropolitan: 11.32%; 
Small metropolitan: 10.97%; 
Rural: 14.23%. 

Year: 2009; 
Large metropolitan: 15.44%; 
Midsized metropolitan: 11.4%; 
Small metropolitan: 10.89%; 
Rural: 14.01%. 

Year: 2010; 
Large metropolitan: 14.39%; 
Midsized metropolitan: 10.87%; 
Small metropolitan: 10.88%; 
Rural: 11.84%. 

Source: GAO analysis of FlightStats data. 

[End of figure] 

Figure 15: Percentage of Delayed Arrival Flights by Community Size, 
Calendar Years 2006-2010: 

[Refer to PDF for image: multiple line graph] 

Percentage of arrivals: 

Year: 2006; 
Large metropolitan: 22.72%; 
Mid-sized metropolitan: 22.71%; 
Small metropolitan: 19.89%; 
Rural: 20.59%. 

Year: 2007; 
Large metropolitan: 24.5%; 
Mid-sized metropolitan: 24.17%; 
Small metropolitan: 22.06%; 
Rural: 22.81%. 

Year: 2008; 
Large metropolitan: 22.34%; 
Mid-sized metropolitan: 21.69%; 
Small metropolitan: 19.99%; 
Rural: 22.93%. 

Year: 2009; 
Large metropolitan: 19.57%; 
Mid-sized metropolitan: 19.24%; 
Small metropolitan: 18.25%; 
Rural: 22.27%. 

Year: 2010; 
Large metropolitan: 19.59%; 
Mid-sized metropolitan: 20.05%; 
Small metropolitan: 18.72%; 
Rural: 21.65%. 

Source: GAO analysis of FlightStats data. 

[End of figure] 

Figure 16: Airline-Reported Sources of Delay in Calendar Year 2010: 

[Refer to PDF for image: pie-chart and horizontal bar graph] 

Sources of delay, Systemwide: 
Extreme weather: 4%; 
National aviation system: 26%; 
Airline: 30%; 
Late arriving aircraft: 39%. 

Sources of delay, by community size: 

Large metropolitan: 
Extreme weather: 4%; 
National aviation system: 28%; 
Airline: 29%; 
Late arriving aircraft: 39%. 

Mid-sized metropolitan: 
Extreme weather: 5%; 
National aviation system: 15%; 
Airline: 39%; 
Late arriving aircraft: 41%. 

Small metropolitan: 
Extreme weather: 5%; 
National aviation system: 16%; 
Airline: 39%; 
Late arriving aircraft: 40%. 

Rural: 
Extreme weather: 7%; 
National aviation system: 16%; 
Airline: 35%; 
Late arriving aircraft: 42%. 

Source: GAO analysis of DOT data. 

Notes: 

1. Numbers may not add to 100 due to rounding. 

2. Security delays do not appear this graphic because they make up 
less than 0.5 percent of the delays. 

[End of figure] 

Figure 17: Airline-Reported Sources of Cancellations in Calendar Year 
2010: 

[Refer to PDF for image: pie-chart and horizontal bar graph] 

Sources of delay, Systemwide: 
National aviation system: 13%; 
Airline: 37%; 
Extreme weather: 50%. 

Sources of delay, by community size: 

Large metropolitan: 
National aviation system: 13%; 
Airline: 36%; 
Extreme weather: 51%. 

Mid-sized metropolitan: 
National aviation system: 15%; 
Airline: 43%; 
Extreme weather: 42%. 

Small metropolitan: 
National aviation system: 14%; 
Airline: 40%; 
Extreme weather: 46%. 

Rural: 
National aviation system: 5%; 
Airline: 20%; 
Extreme weather: 75%. 

Source: GAO analysis of DOT data. 

[End of figure] 

Notes: 

[Refer to PDF for image] 

1. Numbers may not add to 100 due to rounding. 

2. Security delays do not appear on this graphic because they make up 
less than 0.5 percent of cancellations. 

[End of figure] 

[End of section] 

Appendix III: Tarmac Delay Trends Since 2004: 

This appendix provides additional information and illustration of 
tarmac delays of more than 3 hours, from January 2004 through 
September 2010, including how the tarmac delays that occurred during 
this period were distributed by year, month, airport, day of the week, 
and hour. This appendix also provides information on airline-reported 
sources of tarmac delays. This information is based on our analysis of 
DOT data. 

Table 8: Total Number of Tarmac Delays of More than 3 Hours by Stage 
of Operation, January 2004-September 2010: 

Total by year: 2004; 
Taxi-out tarmac delays: 1,169; 
Taxi-in tarmac delays: 70. 

Total by year: 2005; 
Taxi-out tarmac delays: 983; 
Taxi-in tarmac delays: 32. 

Total by year: 2006; 
Taxi-out tarmac delays: 1,220; 
Taxi-in tarmac delays: 58. 

Total by year: 2007; 
Taxi-out tarmac delays: 1,507; 
Taxi-in tarmac delays: 30. 

Total by year: 2008; 
Taxi-out tarmac delays: 1,056; 
Taxi-in tarmac delays: 17. 

Total by year: 2009; 
Taxi-out tarmac delays: 520; 
Taxi-in tarmac delays: 2. 

Total by year: 2010; 
Taxi-out tarmac delays: 72; 
Taxi-in tarmac delays: 4. 

Total by year: Total; 
Taxi-out tarmac delays: 6,527; 
Taxi-in tarmac delays: 213. 

Source: GAO analysis of DOT data. 

Note: Beginning in October 2008, DOT required airlines to submit 
tarmac delay statistics for three additional categories: flights that 
are subsequently canceled or diverted or have multiple gate 
departures. For consistency, we have omitted these flights from this 
figure. Our analysis also excluded flights reported to DOT by Atlantic 
Southeast Airlines, Hawaiian Airlines, and Comair because, according 
to DOT, these airlines inconsistently reported gate returns, prior to 
October 2008. Specifically, some airlines mis-reported the gate- 
departure or takeoff time resulting in an incorrect tarmac delay 
calculation. Further, our analysis excluded data for any flights with 
tarmac delays of more than 10 hours since there were errors in the 
reporting of many such flights. Finally, our analysis did not include 
data for international flights. As a result of these exclusions for 
data reliability purposes, this figure likely under-reports tarmac 
delays of more than 3 hours for these years. See appendix IV for more 
information on recent tarmac delays. 

[End of table] 

Figure 18: Total Number of Tarmac Delays of More than 3 Hours by 
Month, January 2004-September 2010: 

[Refer to PDF for image: line graph] 

Month: January; 
Tarmac delays of more than 3 hours: 488. 

Month: February; 
Tarmac delays of more than 3 hours: 377. 

Month: March; 
Tarmac delays of more than 3 hours: 336. 

Month: April; 
Tarmac delays of more than 3 hours: 188. 

Month: May; 
Tarmac delays of more than 3 hours: 574. 

Month: June; 
Tarmac delays of more than 3 hours: 1,448. 

Month: July; 
Tarmac delays of more than 3 hours: 1,446. 

Month: August; 
Tarmac delays of more than 3 hours: 656. 

Month: September; 
Tarmac delays of more than 3 hours: 313. 

Month: October; 
Tarmac delays of more than 3 hours: 299. 

Month: November; 
Tarmac delays of more than 3 hours: 215. 

Month: December; 
Tarmac delays of more than 3 hours: 400. 

Source: GAO analysis of DOT data. 

Note: Beginning in October 2008, DOT required airlines to submit 
tarmac delay statistics for three additional categories: flights that 
are subsequently canceled or diverted or have multiple gate 
departures. For consistency, we have omitted these flights from this 
figure. Our analysis also excluded flights reported to DOT by Atlantic 
Southeast Airlines, Hawaiian Airlines, and Comair because, according 
to DOT, these airlines inconsistently reported gate returns, prior to 
October 2008. Specifically, some airlines mis-reported the gate- 
departure or takeoff time resulting in an incorrect tarmac delay 
calculation. Further, our analysis excluded data for any flights with 
tarmac delays of more than 10 hours since there were errors in the 
reporting of many such flights. Finally, our analysis did not include 
data for international flights. As a result of these exclusions for 
data reliability purposes, this figure likely under-reports tarmac 
delays of more than 3 hours for these years. See appendix IV for more 
information on recent tarmac delays. 

[End of figure] 

Figure 19: Airline-Reported Sources of Delay for all Tarmac Delays of 
More than 3 Hours, January 2004-September 2010: 

[Refer to PDF for image: pie-chart] 

National airspace system: 86.4%; 
Late arriving aircraft: 6.2%; 
Extreme weather: 4.8%; 
Air carrier: 2.6%. 

Source: GAO analysis of DOT data. 

Notes: 

1. Numbers may not add up to 100 due to rounding. 

2. Security delays do not appear on this graphic because they make up 
less than 1 percent of delays at these airports. DOT collects 
cancellation causal data in one of four categories: (1) national 
aviation system (a broad set of circumstances affecting airline 
flights, such as nonextreme weather that slows down the system, but 
does not prevent flying), (2) airline (any delay that was within the 
control of the airlines, such as aircraft cleaning, baggage loading, 
crew issues, or maintenance), (3) extreme weather (serious weather 
conditions that prevent the operation of a flight, such as tornadoes, 
snowstorms, or hurricanes), and (4) security (such as, evacuation of 
an airport, reboarding because of a security breach, and long lines at 
the passenger screening areas). According to DOT, airlines cannot 
report "late arriving aircraft" as a reason for a canceled flight 
(though they can assign that cause to delayed flights) since 
ultimately this reason would fall under the airline category because 
airlines can have a spare aircraft available when flights arrive late. 
Therefore, "late arriving aircraft" is an airline related cause for a 
cancellation that an airline could have prevented. Beginning in 
October 2008, DOT required airlines to submit tarmac delay statistics 
for three additional categories: flights that are subsequently 
canceled or diverted or have multiple gate departures, prior to 
October 2008. For consistency, we have omitted these flights from this 
figure. Our analysis also excluded flights reported to DOT by Atlantic 
Southeast Airlines, Hawaiian Airlines, and Comair because, according 
to DOT, these airlines inconsistently reported gate returns. 
Specifically, some airlines mis-reported the gate-departure or takeoff 
time resulting in an incorrect tarmac delay calculation. Further, our 
analysis excluded data for any flights with tarmac delays of more than 
10 hours since there were errors in the reporting of many such 
flights. Finally, our analysis did not include data for international 
flights. As a result of these exclusions for data reliability 
purposes, this figure likely under-reports tarmac delays of more than 
3 hours for these years. See appendix IV for more information on 
recent tarmac delays. 

[End of figure] 

Table 9: Total Number of Tarmac Delays of More than 3 Hours at 35 
Airports and Systemwide, January 2004-September 2010: 

Airport: Atlanta Hartsfield International; 
Taxi-out tarmac delays: 240; 
Taxi-in tarmac delays: 3. 

Airport: Baltimore-Washington International; 
Taxi-out tarmac delays: 65; 
Taxi-in tarmac delays: 6. 

Airport: Boston Logan International; 
Taxi-out tarmac delays: 140; 
Taxi-in tarmac delays: 7. 

Airport: Charlotte/Douglas International; 
Taxi-out tarmac delays: 123; 
Taxi-in tarmac delays: 2. 

Airport: Chicago Midway; 
Taxi-out tarmac delays: 39; 
Taxi-in tarmac delays: 0. 

Airport: Chicago O'Hare International; 
Taxi-out tarmac delays: 736; 
Taxi-in tarmac delays: 3. 

Airport: Cincinnati-Northern Kentucky; 
Taxi-out tarmac delays: 75; 
Taxi-in tarmac delays: 3. 

Airport: Cleveland-Hopkins International; 
Taxi-out tarmac delays: 29; 
Taxi-in tarmac delays: 1. 

Airport: Dallas-Fort Worth International; 
Taxi-out tarmac delays: 436; 
Taxi-in tarmac delays: 11. 

Airport: Denver International; 
Taxi-out tarmac delays: 75; 
Taxi-in tarmac delays: 2. 

Airport: Detroit Metro Wayne County; 
Taxi-out tarmac delays: 51; 
Taxi-in tarmac delays: 2. 

Airport: Fort Lauderdale-Hollywood International; 
Taxi-out tarmac delays: 25; 
Taxi-in tarmac delays: 3. 

Airport: George Bush Intercontinental; 
Taxi-out tarmac delays: 284; 
Taxi-in tarmac delays: 5. 

Airport: Greater Pittsburgh International; 
Taxi-out tarmac delays: 28; 
Taxi-in tarmac delays: 1. 

Airport: Lambert St. Louis International; 
Taxi-out tarmac delays: 17; 
Taxi-in tarmac delays: 0. 

Airport: Las Vegas McCarran International; 
Taxi-out tarmac delays: 10; 
Taxi-in tarmac delays: 8. 

Airport: Los Angeles International; 
Taxi-out tarmac delays: 15; 
Taxi-in tarmac delays: 17. 

Airport: Memphis International; 
Taxi-out tarmac delays: 26; 
Taxi-in tarmac delays: 2. 

Airport: Miami International; 
Taxi-out tarmac delays: 57; 
Taxi-in tarmac delays: 3. 

Airport: Minneapolis-St Paul International; 
Taxi-out tarmac delays: 55; 
Taxi-in tarmac delays: 2. 

Airport: New York John F. Kennedy International; 
Taxi-out tarmac delays: 888; 
Taxi-in tarmac delays: 0. 

Airport: New York LaGuardia; 
Taxi-out tarmac delays: 495; 
Taxi-in tarmac delays: 6. 

Airport: Newark International; 
Taxi-out tarmac delays: 865; 
Taxi-in tarmac delays: 1. 

Airport: Orlando International; 
Taxi-out tarmac delays: 27; 
Taxi-in tarmac delays: 6. 

Airport: Philadelphia International; 
Taxi-out tarmac delays: 588; 
Taxi-in tarmac delays: 2. 

Airport: Phoenix Sky Harbor International; 
Taxi-out tarmac delays: 16; 
Taxi-in tarmac delays: 2. 

Airport: Portland International; 
Taxi-out tarmac delays: 1; 
Taxi-in tarmac delays: 2. 

Airport: Ronald Reagan National; 
Taxi-out tarmac delays: 143; 
Taxi-in tarmac delays: 4. 

Airport: Salt Lake City International; 
Taxi-out tarmac delays: 34; 
Taxi-in tarmac delays: 1. 

Airport: San Diego International Lindbergh; 
Taxi-out tarmac delays: 0; 
Taxi-in tarmac delays: 6. 

Airport: San Francisco International; 
Taxi-out tarmac delays: 6; 
Taxi-in tarmac delays: 5. 

Airport: Seattle -Tacoma International; 
Taxi-out tarmac delays: 4; 
Taxi-in tarmac delays: 4. 

Airport: Tampa International; 
Taxi-out tarmac delays: 16; 
Taxi-in tarmac delays: 5. 

Airport: Washington Dulles International; 
Taxi-out tarmac delays: 208; 
Taxi-in tarmac delays: 4. 

Airport: Systemwide; 
Taxi-out tarmac delays: 6,527; 
Taxi-in tarmac delays: 213. 

Source: GAO analysis of DOT data. 

Note: According to FAA, the 35 Operational Evolution Partnership 
airports listed above are commercial airports with significant 
activity and were selected in 2000 on the basis of lists from FAA and 
Congress as well as a study that identified the most congested 
airports in the United States. Beginning in October 2008, DOT required 
airlines to submit tarmac delay statistics for three additional 
categories: flights that are subsequently canceled or diverted or have 
multiple gate departures. For consistency, we have omitted these 
flights from this figure. Our analysis also excluded flights reported 
to DOT by Atlantic Southeast Airlines, Hawaiian Airlines, and Comair 
because, according to DOT, these airlines inconsistently reported gate 
returns. Specifically, some airlines miss-reported the gate-departure 
or takeoff time resulting in an incorrect tarmac delay calculation. 
Further, our analysis excluded data for any flights with tarmac delays 
of more than 10 hours since there were errors in the reporting of many 
such flights. Finally, our analysis did not include data for 
international flights. As a result of these exclusions for data 
reliability purposes, this figure likely under-reports tarmac delays 
of more than 3 hours for these years. See appendix IV for more 
information on recent tarmac delays. 

[End of table] 

Table 10: Total Number of Tarmac Delays of More than 3 Hours by Day of 
the Week, January 2004-September 2010: 

Day of the week: Monday; 
Number of tarmac delays: 714. 

Day of the week: Tuesday; 
Number of tarmac delays: 1,145. 

Day of the week: Wednesday; 
Number of tarmac delays: 1,395. 

Day of the week: Thursday; 
Number of tarmac delays: 1,375. 

Day of the week: Friday; 
Number of tarmac delays: 914. 

Day of the week: Saturday; 
Number of tarmac delays: 431. 

Day of the week: Sunday; 
Number of tarmac delays: 766. 

Day of the week: Total; 
Number of tarmac delays: 6,740. 

Source: GAO analysis of DOT data. 

Note: Beginning in October 2008, DOT required airlines to submit 
tarmac delay statistics for three additional categories: flights that 
are subsequently canceled or diverted or have multiple gate 
departures. For consistency, we have omitted these flights from this 
figure. Our analysis also excluded flights reported to DOT by Atlantic 
Southeast Airlines, Hawaiian Airlines, and Comair because, according 
to DOT, these airlines inconsistently reported gate returns, prior to 
October 2008. Specifically, some airlines mis-reported the gate- 
departure or takeoff time resulting in an incorrect tarmac delay 
calculation. Further, our analysis excluded data for any flights with 
tarmac delays of more than 10 hours since there were errors in the 
reporting of many such flights. Finally, our analysis did not include 
data for international flights. As a result of these exclusions for 
data reliability purposes, this figure likely under-reports tarmac 
delays of more than 3 hours for these years. See appendix IV for more 
information on recent tarmac delays. 

[End of table] 

Table 11: Total Number of Tarmac Delays of More than 3 Hours by Hour, 
January 2004-September 2010: 

Departure hour: 12:00 a.m.; 
Taxi-out tarmac delays: 1; 
Taxi-in tarmac delays: 0; 
Total: 1. 

Departure hour: 5:00 a.m.; 
Taxi-out tarmac delays: 23; 
Taxi-in tarmac delays: 0; 
Total: 23. 

Departure hour: 6:00 a.m.; 
Taxi-out tarmac delays: 135; 
Taxi-in tarmac delays: 5; 
Total: 140. 

Departure hour: 7:00 a.m.; 
Taxi-out tarmac delays: 229; 
Taxi-in tarmac delays: 13; 
Total: 242. 

Departure hour: 8:00 a.m.; 
Taxi-out tarmac delays: 215; 
Taxi-in tarmac delays: 10; 
Total: 225. 

Departure hour: 9:00 a.m.; 
Taxi-out tarmac delays: 192; 
Taxi-in tarmac delays: 4; 
Total: 196. 

Departure hour: 10:00 a.m.; 
Taxi-out tarmac delays: 152; 
Taxi-in tarmac delays: 5; 
Total: 157. 

Departure hour: 11:00 a.m.; 
Taxi-out tarmac delays: 193; 
Taxi-in tarmac delays: 14; 
Total: 207. 

Departure hour: 12:00 p.m.; 
Taxi-out tarmac delays: 269; 
Taxi-in tarmac delays: 18; 
Total: 287. 

Departure hour: 1:00 p.m.; 
Taxi-out tarmac delays: 526; 
Taxi-in tarmac delays: 13; 
Total: 539. 

Departure hour: 2:00 p.m.; 
Taxi-out tarmac delays: 557; 
Taxi-in tarmac delays: 20; 
Total: 577. 

Departure hour: 3:00 p.m.; 
Taxi-out tarmac delays: 747; 
Taxi-in tarmac delays: 21; 
Total: 768. 

Departure hour: 4:00 p.m.; 
Taxi-out tarmac delays: 716; 
Taxi-in tarmac delays: 21; 
Total: 737. 

Departure hour: 5:00 p.m.; 
Taxi-out tarmac delays: 894; 
Taxi-in tarmac delays: 27; 
Total: 921. 

Departure hour: 6:00 p.m.; 
Taxi-out tarmac delays: 717; 
Taxi-in tarmac delays: 19; 
Total: 736. 

Departure hour: 7:00 p.m.; 
Taxi-out tarmac delays: 507; 
Taxi-in tarmac delays: 9; 
Total: 516. 

Departure hour: 8:00 p.m.; 
Taxi-out tarmac delays: 331; 
Taxi-in tarmac delays: 9; 
Total: 340. 

Departure hour: 9:00 p.m.; 
Taxi-out tarmac delays: 94; 
Taxi-in tarmac delays: 3; 
Total: 97. 

Departure hour: 10:00 p.m.; 
Taxi-out tarmac delays: 25; 
Taxi-in tarmac delays: 1; 
Total: 26. 

Departure hour: 11:00 p.m.; 
Taxi-out tarmac delays: 4; 
Taxi-in tarmac delays: 1; 
Total: 5. 

Departure hour: Total; 
Taxi-out tarmac delays: 6,527; 
Taxi-in tarmac delays: 213; 
Total: 6,740. 

Source: GAO analysis of DOT data. 

Note: Beginning in October 2008, DOT required airlines to submit 
tarmac delay statistics for three additional categories: flights that 
are subsequently canceled or diverted or have multiple gate 
departures. For consistency, we have omitted these flights from this 
figure. Our analysis also excluded flights reported to DOT by Atlantic 
Southeast Airlines, Hawaiian Airlines, and Comair because, according 
to DOT, these airlines inconsistently reported gate returns, prior to 
October 2008. Specifically, some airlines mis-reported the gate- 
departure or takeoff time resulting in an incorrect tarmac delay 
calculation. Further, our analysis excluded data for any flights with 
tarmac delays of more than 10 hours since there were errors in the 
reporting of many such flights. Finally, our analysis did not include 
data for international flights. As a result of these exclusions for 
data reliability purposes, this figure likely under-reports tarmac 
delays of more than 3 hours for these years. See appendix IV for more 
information on recent tarmac delays. 

[End of table] 

[End of section] 

Appendix IV: Tarmac Delay Trends since October 2008: 

Beginning in October 2008, DOT required airlines to submit data on 
flights with tarmac delays that were subsequently canceled, diverted, 
or had multiple gate departures (see table 12). Previously, DOT had 
only captured tarmac delays that occurred during taxi-out or during 
taxi-in. While the majority of tarmac delays happen at taxi-out or 
taxi-in, the change in reporting captured data for some additional 
tarmac delays of more than 3 hours. As a result of these new reporting 
requirements, tarmac delays are now captured: 

* during taxi-out: the time between when a flight departs the gate at 
the origin airport and when it lifts off from that airport (wheels-
off); 

* during taxi-in: the time between a flight touching down at its 
destination airport (wheels-on) and arriving at the gate; 

* prior to cancellation: flight left the gate but was canceled at the 
origin airport; 

* during a diversion: the tarmac time experienced at an airport other 
than the destination airport; or: 

* as a result of a multiple gate departure: the flight left the gate, 
then returned, and then left again; the tarmac time is the time before 
the return to the gate. 

Table 12: Tarmac Delays of More than 3 Hours, October 2008-December 
2010: 

Tarmac times: October 2008: Total. 

Month: October 2008; 
Tarmac times: Total: 46; 
Tarmac times: Percentage of regularly scheduled flights: 0.01%; 
Stage of operation: 
Prior To cancellation: 2; 
Multiple gate departure: 5; 
Taxi-out: 33; 
Taxi-in: 0; 
At diversion airport: 6; 
Number of regularly scheduled flights: 556,205. 

Month: November 2008; 
Tarmac times: Total: 7; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 1; 
Taxi-out: 4; 
Taxi-in: 0; 
At diversion airport: 2; 
Number of regularly scheduled flights: 523,272. 

Month: December 2008; 
Tarmac times: Total: 183; 
Tarmac times: Percentage of regularly scheduled flights: 0.03; 
Stage of operation: 
Prior To cancellation: 40; 
Multiple gate departure: 13; 
Taxi-out: 113; 
Taxi-in: 7; 
At diversion airport: 10; 
Number of regularly scheduled flights: 544,956. 

Month: January[A] 2009; 
Tarmac times: Total: 85; 
Tarmac times: Percentage of regularly scheduled flights: 0.02; 
Stage of operation: 
Prior To cancellation: 7; 
Multiple gate departure: 10; 
Taxi-out: 68; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 532,339. 

Month: February 2009; 
Tarmac times: Total: 40; 
Tarmac times: Percentage of regularly scheduled flights: 0.01; 
Stage of operation: 
Prior To cancellation: 5; 
Multiple gate departure: 3; 
Taxi-out: 32; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 488,410. 

Month: March 2009; 
Tarmac times: Total: 85; 
Tarmac times: Percentage of regularly scheduled flights: 0.02; 
Stage of operation: 
Prior To cancellation: 6; 
Multiple gate departure: 9; 
Taxi-out: 63; 
Taxi-in: 0; 
At diversion airport: 7; 
Number of regularly scheduled flights: 557,422. 

Month: April 2009; 
Tarmac times: Total: 74; 
Tarmac times: Percentage of regularly scheduled flights: 0.01; 
Stage of operation: 
Prior To cancellation: 10; 
Multiple gate departure: 8; 
Taxi-out: 45; 
Taxi-in: 0; 
At diversion airport: 11; 
Number of regularly scheduled flights: 537,793. 

Month: May 2009; 
Tarmac times: Total: 34; 
Tarmac times: Percentage of regularly scheduled flights: 0.01; 
Stage of operation: 
Prior To cancellation: 7; 
Multiple gate departure: 2; 
Taxi-out: 24; 
Taxi-in: 1; 
At diversion airport: 0; 
Number of regularly scheduled flights: 546,832. 

Month: June 2009; 
Tarmac times: Total: 268; 
Tarmac times: Percentage of regularly scheduled flights: 0.05; 
Stage of operation: 
Prior To cancellation: 38; 
Multiple gate departure: 40; 
Taxi-out: 167; 
Taxi-in: 1; 
At diversion airport: 22; 
Number of regularly scheduled flights: 557,594. 

Month: July 2009; 
Tarmac times: Total: 161; 
Tarmac times: Percentage of regularly scheduled flights: 0.03; 
Stage of operation: 
Prior To cancellation: 21; 
Multiple gate departure: 20; 
Taxi-out: 102; 
Taxi-in: 0; 
At diversion airport: 18; 
Number of regularly scheduled flights: 580,134. 

Month: August 2009; 
Tarmac times: Total: 66; 
Tarmac times: Percentage of regularly scheduled flights: 0.01; 
Stage of operation: 
Prior To cancellation: 6; 
Multiple gate departure: 10; 
Taxi-out: 43; 
Taxi-in: 0; 
At diversion airport: 7; 
Number of regularly scheduled flights: 568,301. 

Month: September 2009; 
Tarmac times: Total: 6; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 0; 
Taxi-out: 4; 
Taxi-in: 0; 
At diversion airport: 2; 
Number of regularly scheduled flights: 510,852. 

Month: October 2009; 
Tarmac times: Total: 11; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 0; 
Taxi-out: 11; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 531,799. 

Month: November 2009; 
Tarmac times: Total: 4; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 1; 
Taxi-out: 2; 
Taxi-in: 0; 
At diversion airport: 1; 
Number of regularly scheduled flights: 509,540. 

Month: December 2009; 
Tarmac times: Total: 34; 
Tarmac times: Percentage of regularly scheduled flights: 0.01; 
Stage of operation: 
Prior To cancellation: 4; 
Multiple gate departure: 3; 
Taxi-out: 22; 
Taxi-in: 0; 
At diversion airport: 5; 
Number of regularly scheduled flights: 529,269. 

Month: January 2010; 
Tarmac times: Total: 20; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 1; 
Multiple gate departure: 3; 
Taxi-out: 11; 
Taxi-in: 2; 
At diversion airport: 3; 
Number of regularly scheduled flights: 521,809. 

Month: February 2010; 
Tarmac times: Total: 60; 
Tarmac times: Percentage of regularly scheduled flights: 0.01; 
Stage of operation: 
Prior To cancellation: 5; 
Multiple gate departure: 1; 
Taxi-out: 52; 
Taxi-in: 1; 
At diversion airport: 1; 
Number of regularly scheduled flights: 483,270. 

Month: March 2010; 
Tarmac times: Total: 25; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 9; 
Multiple gate departure: 2; 
Taxi-out: 11; 
Taxi-in: 1; 
At diversion airport: 2; 
Number of regularly scheduled flights: 549,262. 

Month: April 2010; 
Tarmac times: Total: 4; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 0; 
Taxi-out: 1; 
Taxi-in: 0; 
At diversion airport: 3; 
Number of regularly scheduled flights: 529,330. 

Month: May 2010; 
Tarmac times: Total: 1; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 0; 
Taxi-out: 1; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 542,747. 

Month: June 2010; 
Tarmac times: Total: 3; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 2; 
Multiple gate departure: 0; 
Taxi-out: 1; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 551,687. 

Month: July 2010; 
Tarmac times: Total: 3; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 3; 
Multiple gate departure: 0; 
Taxi-out: 0; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 570,788. 

Month: August 2010; 
Tarmac times: Total: 1; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 0; 
Taxi-out: 0; 
Taxi-in: 0; 
At diversion airport: 1; 
Number of regularly scheduled flights: 569,217. 

Month: September 2010; 
Tarmac times: Total: 4; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 2; 
Multiple gate departure: 2; 
Taxi-out: 0; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 526,107. 

Month: October 2010; 
Tarmac times: Total: 0; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 0; 
Taxi-out: 0; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 545,519. 

Month: November 2010; 
Tarmac times: Total: 0; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 0; 
Multiple gate departure: 0; 
Taxi-out: 0; 
Taxi-in: 0; 
At diversion airport: 0; 
Number of regularly scheduled flights: 520,999. 

Month: December 2010; 
Tarmac times: Total: 3; 
Tarmac times: Percentage of regularly scheduled flights: 0; 
Stage of operation: 
Prior To cancellation: 1; 
Multiple gate departure: 1; 
Taxi-out: 0; 
Taxi-in: 0; 
At diversion airport: 1; 
Number of regularly scheduled flights: 539,382. 

Source: DOT. 

[A] According to DOT, January 2009 includes one flight with two 
separate 3-hour tarmac times. Northwest Flight 1491, on January 28, 
2009, was on the tarmac for 188 minutes before returning to the gate. 
The flight departed the gate a second time and was on the tarmac for 
199 minutes before wheels-off. Details of the flight are listed as a 3-
hour multiple gate departure delay and a 3-hour taxi-out delay. 

[End of table] 

Table 13: Tarmac Delays of More than 3 Hours, May 2010-April 2011: 

Date: 5/28/10; 
Stage of flight: During taxi-out; 
Airline: Delta Air Lines; 
Origin: ATL; 
Destination: DFW; 
Delay or cancellation cause: National aviation system; 
Minutes over 3 hours: 2; 
DOT outcome: No violation. 

Date: 6/18/10; 
Stage of flight: Prior to cancellation; 
Airline: United Airlines; 
Origin: ORD; 
Destination: LGA; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 5; 
DOT outcome: Violation; airline warned. 

Date: 6/18/10; 
Stage of flight: Prior to cancellation; 
Airline: United Airlines; 
Origin: ORD; 
Destination: ATL; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 3; 
DOT outcome: Violation; airline warned. 

Date: 6/18/10; 
Stage of flight: During taxi-out; 
Airline: United Airlines; 
Origin: ORD; 
Destination: IAD; 
Delay or cancellation cause: National aviation system; 
Minutes over 3 hours: 2; 
DOT outcome: Violation; airline warned. 

Date: 7/23/10; 
Stage of flight: Prior to cancellation; 
Airline: American Eagle; 
Origin: ORD; 
Destination: BNA; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 34; 
DOT outcome: No violation. 

Date: 7/23/10; 
Stage of flight: Prior to cancellation; 
Airline: American Eagle; 
Origin: ORD; 
Destination: RDU; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 19; 
DOT outcome: No violation. 

Date: 7/23/10; 
Stage of flight: Prior to cancellation; 
Airline: American Eagle; 
Origin: ORD; 
Destination: BWI; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 18; 
DOT outcome: No violation. 

Date: 8/5/10; 
Stage of flight: At diversion airport; 
Airline: United Airlines; 
Origin: SJU; 
Destination: IAD; 
Delay or cancellation cause: n/a; 
Minutes over 3 hours: 20; 
DOT outcome: No violation. 

Date: 9/22/10; 
Stage of flight: Prior to cancellation; 
Airline: US Airways; 
Origin: JFK; 
Destination: CLT; 
Delay or cancellation cause: Air carrier; 
Minutes over 3 hours: 17; 
DOT outcome: No violation. 

Date: 9/22/10; 
Stage of flight: Prior to cancellation; 
Airline: Delta Air Lines; 
Origin: PHL; 
Destination: DTW; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 3; 
DOT outcome: No violation. 

Date: 9/22/10; 
Stage of flight: During multiple gate departure; 
Airline: Southwest; 
Origin: PHL; 
Destination: STL; 
Delay or cancellation cause: Extreme weather and national aviation 
system; 
Minutes over 3 hours: 19; 
DOT outcome: Violation; airline warned. 

Date: 9/22/10; 
Stage of flight: During multiple gate departure; 
Airline: Pinnacle; 
Origin: JFK; 
Destination: ORD; 
Delay or cancellation cause: Extreme weather and national aviation 
system; 
Minutes over 3 hours: 5; 
DOT outcome: No violation. 

Date: 12/12/10; 
Stage of flight: During multiple gate departure; 
Airline: Delta Air Lines; 
Origin: DTW; 
Destination: MIA; 
Delay or cancellation cause: Extreme weather and national aviation 
system; 
Minutes over 3 hours: 12; 
DOT outcome: No violation. 

Date: 12/12/10; 
Stage of flight: Prior to cancellation; 
Airline: Pinnacle; 
Origin: DTW; 
Destination: CID; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 6; 
DOT outcome: No violation. 

Date: 12/27/10; 
Stage of flight: At diversion airport; 
Airline: United Airlines; 
Origin: SAN; 
Destination: SFO; 
Delay or cancellation cause: n/a; 
Minutes over 3 hours: 9; 
DOT outcome: No violation. 

Date: 1/10/11; 
Stage of flight: Prior to cancellation; 
Airline: Delta Air Lines; 
Origin: ATL; 
Destination: HNL; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 31; 
DOT outcome: Under investigation. 

Date: 4/24/11; 
Stage of flight: Prior to cancellation; 
Airline: United Airlines; 
Origin: JFK; 
Destination: SFO; 
Delay or cancellation cause: Extreme weather; 
Minutes over 3 hours: 22; 
DOT outcome: Under investigation. 

Date: 4/27/11; 
Stage of flight: Prior to cancellation; 
Airline: Delta Air Lines; 
Origin: ATL; 
Destination: SLC; 
Delay or cancellation cause: Air carrier; 
Minutes over 3 hours: 22; 
DOT outcome: Under investigation. 

Date: 4/27/11; 
Stage of flight: Prior to cancellation; 
Airline: Delta Air Lines; 
Origin: ATL; 
Destination: ONT; 
Delay or cancellation cause: Air carrier; 
Minutes over 3 hours: 20; 
DOT outcome: Under investigation. 

Date: 4/27/11; 
Stage of flight: During taxi-out; 
Airline: Delta Air LInes; 
Origin: ATL; 
Destination: FLL; 
Delay or cancellation cause: National aviation system and air carrier; 
Minutes over 3 hours: 5; 
DOT outcome: Under investigation. 

Source: GAO analysis of DOT data. 

Note: ATL (Atlanta Hartsfield International), BNA (Nashville 
International Airport), BWI (Baltimore-Washington International), CID 
(Cedar Rapids Iowa), CLT (Charlotte/Douglas International), DFW 
(Dallas-Fort Worth International), DTW (Detroit Metro Wayne County), 
FLL (Fort Lauderdale Hollywood International), HNL (Honolulu 
International), IAD (Washington Dulles International), JFK (New York 
John F. Kennedy International), LGA (LaGuardia International), MIA 
(Miami International), ONT (Ontario International), ORD (Chicago 
O'Hare International), PHL (Philadelphia International), RDU (Raleigh-
Durham International Airport), SAN (San Diego International 
Lindbergh), SFO (San Francisco International), SJU (Luis Munoz Marin 
International Airport), SLC (Salt Lake City International), and STL 
(Lambert St. Louis International). 

[End of table] 

[End of section] 

Appendix V: Tarmac Delay Logistic Regression Analysis: 

This appendix describes two models that we designed to assess whether 
DOT's tarmac delay rule is correlated with an increase in airline 
cancellations. Both models use data for the same months before and 
after the rule went into effect to analyze whether and how a variety 
of factors--including the imposition of the rule--are associated with 
the likelihood (or odds) that a flight will be canceled. One model 
analyzes the likelihood of cancellation after a flight has left the 
gate and gone onto the tarmac; the other analyzes the likelihood of 
cancellation at the gate. Specifically, this appendix discusses (1) 
the incidence of cancellations since the rule's implementation, (2) 
the conceptual framework for examining these issues through modeling, 
(3) variable calculations and data sources, and (4) the models' 
results. 

Incidence of Flight Cancellations in 2010 Relative to 2009: 

To examine the incidence of flight cancellations before and after the 
tarmac rule's implementation, we collected data on flights for May 
through September in 2009--before the rule went into effect--and for 
the same months in 2010, after the rule's implementation.[Footnote 
122] We examined the incidence of cancellation for flights that were 
canceled after they left the gate and went onto the tarmac, and for 
flights before they left the gate. The data cover flights reported to 
the Bureau of Transportation Statistics (BTS) at 70 airports in the 
continental United States.[Footnote 123] 

Table 14 provides information, for the time frame of this analysis, on 
the number of flights in each time period that left the gate and took 
off, and the number of flights that left the gate but eventually were 
canceled. From that information we calculate the odds of cancellation 
in each of the two years. These odds equal the number of flights that 
were canceled divided by the number of flights that were not canceled. 
For example, in 2009, the odds of cancellation is (808/1,868,189), 
which equals 0.000433. Thus, roughly 4 out of every 10,000 flights 
that exited the gate were ultimately canceled in that year. Finally, 
we calculated the odds ratio of a flight being canceled in 2010 
compared with 2009, which is a ratio of the odds of cancellation in 
2010 to the odds of cancellation with 2009. 

Table 14: Unadjusted Odds Ratio for Tarmac Cancellation, 2010 versus 
2009: 

Year (May-September): 2009; 
Number of flights not canceled: 1,868,189; 
Number of flights canceled: 808; 
Odds of cancellation: 0.000433. 

Year (May-September): 2010; 
Number of flights not canceled: 1,845,296; 
Number of flights canceled: 992; 
Odds of cancellation: 0.000538. 

Odds ratio, 2010 compared with 2009: 1.24. 

Source: GAO analysis of DOT data. 

Notes: 

1. "Unadjusted" means that this analysis has not controlled for other 
factors that may influence the incidence of cancellation. 

2. These results are based on analysis of all flights, operated by DOT 
reporting airlines, to and from 70 of the FAA's Aviation System 
Performance Metrics 77 airports in the United States and Puerto Rico. 
These results differ from the cancellation trends presented in table 1 
of the report because table 1 illustrated trends by these same 
airlines across the entire system and not just at these 70 airports. 

[End of table] 

The data show that flights are rarely canceled after leaving the gate. 
In both years, a very small fraction of flights that left the gate 
were ultimately canceled. As noted, in 2009 roughly 4 flights (that 
left the gate) were canceled for every 10,000 flights that took off. 
However, the odds of cancellation for a flight that has left the gate 
did appear to rise in 2010 compared with 2009. The odds ratio is the 
odds of a tarmac cancellation in 2010 divided by the odds of such a 
cancellation in 2009. The odds ratio exceeds 1, indicating that 
cancellations were more likely to occur in 2010. Specifically there 
was about a 24 percent increase in the odds of cancellation in 2010 
compared with a year earlier. 

Because we hypothesized that the likelihood of cancellation for a 
flight that has left the gate may be greater the longer it sits on the 
tarmac, we assessed the odds of cancellation based on how long a 
flight sits on the tarmac, as shown in table 15. These data reveal 
that in both 2009 and 2010, the odds of cancellation rise 
substantially for flights that have been on the tarmac for longer 
periods of time. For example, in 2009 the odds of cancellation for 
flights on the tarmac 60 minutes or less are only a small fraction of 
a percent, but for flights on the tarmac for 121 to 180 minutes, the 
odds rise substantially to 6 percent in that year. Using these odds, 
we calculate odds ratios showing the relative odds of cancellation for 
each hour category compared with the base hour (up to 1 hour of 
delay), within each year. As shown, the odds ratios rise dramatically 
as more time passes on the tarmac--a 42-fold increase in the odds of 
cancellation when a plane has been sitting on the tarmac for 61 to 120 
minutes compared with a delay of 60 or less minutes in 2009. 

Table 15: Unadjusted Odds Ratio for Tarmac Cancellation, 2010 versus 
2009, by Time Spent on Tarmac: 

Year (May-September): 2009; 
Time on tarmac (minutes): 0-60; 
Number of flights not canceled: 1,848,276; 
Number of flights canceled: 452; 
Odds of cancellation: 0.000244. 

Year (May-September): 2009; 
Time on tarmac (minutes): 61-120; 
Number of flights not canceled: 17,707; 
Number of flights canceled: 184; 
Odds of cancellation: 0.01039; 
Odds ratio, time on tarmac compared with 0 to 60 minute time, within a 
given year: 42. 

Year (May-September): 2009; 
Time on tarmac (minutes): 121-180; 
Number of flights not canceled: 1,912; 
Number of flights canceled: 116; 
Odds of cancellation: 0.06067; 
Odds ratio, time on tarmac compared with 0 to 60 minute time, within a 
given year: 248. 

Year (May-September): 2010; 
Time on tarmac (minutes): 0-0; 
Number of flights not canceled: 1,830,874; 
Number of flights canceled: 561; 
Odds of cancellation: 0.000306; 
Odds ratio, time on tarmac compared with 0 to 60 minute time, within a 
given year: [Empty]; 
Odds ratio, time on tarmac in 2010 compared with same time on tarmac 
2009: 1.25. 

Year (May-September): 2010; 
Time on tarmac (minutes): 61-120; 
Number of flights not canceled: 13,591; 
Number of flights canceled: 266; 
Odds of cancellation: 0.019571; 
Odds ratio, time on tarmac compared with 0 to 60 minute time, within a 
given year: 63; 
Odds ratio, time on tarmac in 2010 compared with same time on tarmac 
2009: 1.88. 

Year (May-September): 2010; 
Time on tarmac (minutes): 121-180; 
Number of flights not canceled: 829; 
Number of flights canceled: 159; 
Odds of cancellation: 0.191797; 
Odds ratio, time on tarmac compared with 0 to 60 minute time, within a 
given year: 626; 
Odds ratio, time on tarmac in 2010 compared with same time on tarmac 
2009: 3.16. 

Source: GAO analysis of DOT data. 

Notes: 

1. "Unadjusted" means that this analysis has not controlled for other 
factors that may influence the incidence of cancellation. 

2. These values may not exactly equal the values based on division 
because the odds ratios presented here are based on unrounded numbers. 
Data for tarmac delays of more than 3 hours are not included in the 
table because for 2010 the number of such delays was only eight and we 
decided that odds ratios based on such small numbers may not be 
representative. 

3. These results are based on analysis of all flights, operated by DOT 
reporting airlines, to and from 70 of the FAA's Aviation System 
Performance Metrics 77 airports in the United States. and Puerto Rico. 
These results differ from the cancellation trends presented in table 1 
of the report because table 1 illustrated trends by these same 
airlines across the entire system and not just at these 70 airports. 

[End of table] 

These data provided in table 15 also reveal that for every "time-on- 
the-tarmac" category, the odds of cancellation in 2010 exceeded the 
odds of cancellation in 2009 because all of the odds ratios (shown in 
the far right column) exceed 1. We calculated these odds ratios by 
taking the odds of cancellation in one tarmac time category in 2010 
and dividing it by the odds of cancellation for the same tarmac time 
category in 2009. These data further show that the differential 
between the likelihood for cancellation in 2010 over 2009 rose the 
longer a flight was on the tarmac. While the odds of cancellation for 
flights on the tarmac for 60 or less minutes were 25 percent greater 
in 2010 than in 2009, for flights on the tarmac 121 to 180 minutes, 
there was a threefold greater odds of cancellation in 2010 compared to 
2009. Figure 20 shows how the relative odds of flight cancellation in 
2010 compared to 2009 increases the longer a flight sits on the tarmac. 

Figure 20: Odds of Cancellation for Flights on the Tarmac, 2010 and 
2009: 

[Refer to PDF for image: multiple line graph] 

Odds of Cancellation: 

Time on the tarmac: 0-60 minutes; 
2010: 0.000306; 
2009: 0.000244. 

Time on the tarmac: 61-120 minutes; 
2010: 0.019571; 
2009: 0.001039. 

Time on the tarmac: 121-180 minutes; 
2010: 0.191797; 
2009: 0.006067. 

Source: GAO analysis of DOT data. 

[End of figure] 

Finally, we calculated odds ratios to examine the relative odds of 
flight cancellations at the gate in 2010 and 2009. Table 16 shows the 
odds of cancellation each year and the odds ratio for gate 
cancellations in 2010 compared with 2009. The odds of a gate 
cancellation were 13 percent greater in 2010 compared with 2009. 

Table 16: Unadjusted Odds Ratio for Gate Cancellation, 2010 versus 
2009: 

Year (May-September): 2009; 
Number of flights that taxi away from the gate: 1,868,997; 
Number of flights canceled at the gate: 16,850; 
Odds of Gate cancellation: 0.00902. 

Year (May-September): 2010; 
Number of flights that taxi away from the gate: 1,846,288; 
Number of flights canceled at the gate: 18,807; 
Odds of Gate cancellation: 0.01019. 

Odds ratio, 2010 compared with 2009: 1.13. 

Source: GAO analysis of DOT data. 

Notes: 

1. "Unadjusted" means that this analysis has not controlled for other 
factors that may influence the incidence of cancellation. 

2. These results are based on analysis of all flights, operated by DOT 
reporting airlines, to and from 70 of the FAA's Aviation System 
Performance Metrics 77 airports in the United States and Puerto Rico. 
These results differ from the cancellation trends presented in table 1 
of the report because table 1 illustrated trends by these same 
airlines across the entire system and not just at these 70 airports. 

[End of table] 

Conceptual Framework of Models: 

While the unadjusted odds ratios indicate that the likelihood of both 
tarmac and gate cancellations increased in May through September 2010 
relative to the same time period in 2009, this increase may or may not 
be attributable to the tarmac delay rule in 2010. Many factors may 
contribute to flight cancellations, and there could be an observed 
difference across two years for a number of reasons. For example, 
weather events may disrupt traffic more in one year than in another, 
or airline scheduling or traffic patterns could change over time. To 
develop a model to examine this issue, it is helpful to first consider 
whether there is any reason why the tarmac rule might be correlated 
with flight cancellations. In particular, what is it about airline 
behavior that could be influenced by the tarmac delay rule? 

Model Hypothesis: 

When there are flight disruptions, airlines face a trade-off between 
the consequences of delays they might incur and cancellations. For 
example, when bad weather reduces airport capacity, thus slowing the 
rate at which flights can take off or land at an airport, airlines 
must decide how to ration their traffic. They can choose to hold to 
their schedule and fly all their flights, but risk long delays. 
Alternatively, they can choose to cancel some of their flights, thus 
mitigating the capacity constraint they face and reducing the amount 
of delays for their remaining flights. Although airlines have some 
control over these trade-offs, airport capacity--both in gate space 
and on the tarmac--sometimes becomes so constrained that cancellations 
are unavoidable. In managing these circumstances, airlines attempt to 
minimize disruptions to passengers and costs to themselves. How an 
airline makes decisions within the context of this trade-off will vary 
among airlines depending on their business models and the particular 
situation at hand. 

The DOT's tarmac delay rule requires airlines to limit the time 
flights spend on the tarmac to less than 3 hours or face the 
possibility of a substantial fine. Our hypothesis is that if the 
tarmac rule is associated with a greater incidence of flight 
cancellations, this may occur because the rule may have altered 
airlines' calculus in analyzing the trade-off between delay and 
cancellation. According to airline representatives we spoke with, 
flights that sit on the tarmac for a significant period of time may 
have to return to the gate to avoid a fine and, because of crew hour 
limits or because of the severity of the underlying cause of the 
delay, these flights may be canceled. In addition, airline officials 
and aviation stakeholders told us that the rule has increased the 
likelihood that they will precancel a flight--that is, cancel a flight 
before it ever leaves the gate. First, if a flight is returning to the 
terminal to avoid a tarmac fine, a flight that has not yet left the 
gate might need to be canceled to free gate space for the returning 
flight. Airline officials also told us that they are precanceling more 
flights before their scheduled departure time when weather or other 
factors indicate that long tarmac delays are possible. We were also 
told by one airline official that precancelations may be preferable if 
a long tarmac delay seems likely because passengers are likely to have 
more rebooking options if they are precanceled than if they wait for 
some time on the tarmac and attempt to rebook later in the day. 

There are several limitations to this analysis. First, important 
factors related to cancellations may not be controlled for. For 
example, we do not have information on flights that were canceled for 
mechanical problems. This, along with other factors that might be 
relevant, could not be controlled for because we do not have adequate 
data to assess all factors that could be associated with 
cancellations. Also, the analysis provides a suggestion as to the 
factors that are correlated with cancellations, but does not 
necessarily suggest a causal relationship. 

Estimation Method: 

To isolate the correlation between the rule and cancellations, as well 
as to better understand what other key factors are associated with the 
rate of cancellations, we developed two models to examine whether the 
rule may be correlated with a change in the incidence of flight 
cancellations. Because we are estimating the likelihood of a discreet 
event--whether a given flight is canceled--we applied a logistic 
regression (or logit method) for the estimation. This method enables 
us to assess how each of a set of independent factors correlates with 
the odds of a binary event--in this case the cancellation or 
noncancellation of an airline flight. We examined two contexts in 
which a flight may be canceled, after some time on the tarmac or at 
the gate.[Footnote 124] 

Tarmac-cancellation model. In the first model, we assessed whether 
flights that left the gate were more likely to be canceled during May 
through September 2010 than during the same time period in 2009. 
Although the tarmac rule considers fines only for flights on the 
tarmac more than 3 hours, our discussions with airline officials and 
experts suggested that airlines begin to assess the risk of tarmac 
violation well before prolonged tarmac delay begins. We grouped 
flights into hour-long categories based on the amount of time a flight 
sat on the tarmac in order to assess whether the length of time on the 
tarmac is associated with the odds of cancellation. For example, if a 
flight sat on the tarmac for 72 minutes, we placed it in the 60 to 121 
minutes tarmac time category. For the tarmac-cancellation model, we 
assessed 3,715,219 flight records for the 10 months included in the 
model; 1,799 of these were ultimately canceled. 

Gate-cancellation model. In the second model, we examined whether 
flights were more likely to be precanceled after the rule went into 
effect. A precancellation occurs when a scheduled flight is canceled 
before it ever leaves the gate. Thus, even a flight that goes onto the 
tarmac but is later canceled is treated as a flight that was not 
canceled at the gate in this analysis. This model included 3,750,868 
flight records, of which 35,649 were precanceled at the gate. 

Many factors affect the possibility of a flight's cancellation and, 
therefore, we attempted to account for these other factors in the 
model. By controlling for this array of other influences on 
cancellations, the model is designed to determine whether the tarmac 
rule is independently correlated with the odds of a flight being 
canceled. Based on our research and discussions with airline 
representatives and academic experts, we identified factors that 
contribute to flight cancellations, including factors related to (1) 
the origin and destination airports, including circumstances at those 
airports at the time a flight is scheduled to depart, such as weather 
conditions; (2) characteristics of specific airlines and their 
operations; and (3) the scheduled city-pair route and the individual 
flight. Our hypothesis is that these same factors contribute to both 
types of cancellations, although we do not expect that the 
relationship between any of the factors and the odds of cancellation 
will necessarily be exactly the same in the two models. Each specific 
variable and its data source are discussed below. 

Variables and Data Sources: 

The primary source of data for the model is flight level data from 
BTS's ASQP system. This system includes flight-level data, each record 
of which provides an array of information about a single-leg 
flight,[Footnote 125] such as the origin and destination airports, the 
date and time the flight was scheduled to depart and arrive, the 
airline, the taxi-out time, cause of any delay, and whether the flight 
was canceled. The BTS data form the level of observation for the 
models--which is a given flight--and data from other sources are 
merged into these observations. Airlines that account for at least 1 
percent of total domestic scheduled passenger service revenue are 
required to file this flight information with BTS. Because this 
required filing leaves out smaller airlines, not all flights are 
included in the model. Moreover, our analysis includes data for 70 
airports. The remainder of this section describes the rationale for 
including each of the variables in the model, how each is calculated, 
and the source of the data. 

The dependent variable. The dependent variable for the two models is a 
dummy variable--that is a variable that takes a value of one or zero 
depending on the presence or absence of some characteristic. For the 
tarmac-cancellation model this variable takes a value of one if a 
flight that left the gate returned to the gate after going onto the 
tarmac and then was canceled, and otherwise takes a value of zero. For 
the gate-cancellation model, the variable is set to one if the flight 
was canceled before taxiing out from the gate and is otherwise set to 
zero. 

Variable of interest: implementation of tarmac delay rule. In both 
models, we include data on flights from May through September in 2009 
and for the same months in 2010. Since the rule went into effect in 
late April 2010, a dummy variable indicating whether a flight took 
place in 2010 is used. For the tarmac model we also include a set of 
dummy variables indicating how long a flight was on the tarmac before 
taking off or arriving back at the gate. We classify hour-long 
categories of tarmac time: 0 to 60 minutes, 61 to 120 minutes, 121 to 
180 minutes, and more than 180 minutes, and include three dummy 
variables (using the 0 to 60 minute tarmac time as the reference 
category and therefore leaving it out of the regression) to test 
whether cancellations become more likely with longer tarmac times. 
Additionally, we multiply these three dummy variables by the dummy 
variable indicating whether the flight took place in 2009 or 2010. 
Creating such interactions allows the measured impact of the tarmac 
time on cancellation to be different before and after the 
implementation of the tarmac delay rule. Thus, we include six time-on- 
tarmac dummy variables in the tarmac delay model. 

Variables related to airports and conditions at airports. Several of 
the independent factors that might affect the odds of a flight being 
canceled are related to the airports at which a flight begins and ends 
and certain conditions at those airports: 

* Dummy variables for congested airports. It is well known that 
certain airports suffer more than others from congestion and delays. 
Because some airports have more delay-related issues, we believe that 
flights involving these airports may be more likely to be canceled, 
holding other factors constant. In a previous report we found that, 
according to FAA data, seven airports were the source of 80 percent of 
departure delays.[Footnote 126] Because this issue could affect 
flights both on the tarmac and at the gate, we use two dummy variables 
in both models to denote whether a flight either started or ended at 
one of these seven airports. We expect that flights involving these 
airports are more likely to be canceled. 

* Endpoint airport weather conditions. One of the factors likely to 
influence flight cancellations is the weather. Certain weather 
conditions can disrupt an airport's realized capacity level and cause 
traffic to flow more slowly or even halt for a time. We obtained data 
from the FAA for the National Oceanic and Atmospheric Administration's 
reporting of weather conditions for each hour at each of the airports 
included in our model. The data source provided information on the 
incidence of 32 types of weather conditions, such as fog, snow, 
thunderstorms, and hail. Additionally, FAA ranks each of the 32 
weather conditions from 1 to 3 to indicate the impact of that 
particular weather condition on aviation activity. For example, 
thunderstorms can be highly disruptive to air traffic and is assigned 
a value of 3, while rain is assigned a value of 2, and haze a value of 
1, indicating that haze usually presents only minor problems for air 
traffic. Using these data, we developed two variables to denote the 
occurrence of potentially disruptive weather conditions at the origin 
or the destination airport around the time a flight was scheduled for 
departure or arrival, respectively. In particular, to characterize the 
weather at the origin airport, we designated the hour of scheduled 
departure as the anchor timeframe, but we also took into account 
weather conditions in the hour before and the hour after the scheduled 
takeoff. This variable is set to 1 if a weather condition with a value 
of 3 (a significant weather condition) existed at the origin airport 
during the hour before, at the hour of, or the hour after the 
scheduled departure time. Similarly, the second variable is set to 1 
if a weather event of value 3 occurred at the destination airport 
within the 3-hour window around the scheduled arrival time of the 
flight. Poor weather is expected to be associated with a greater 
likelihood of cancellation for flights already on the tarmac as well 
as those at the gate. 

* Ground delays and ground stops. This variable considers whether FAA 
has initiated programs to slow or stop traffic at an airport because 
of weather conditions, congestion, or some other reason. We obtained 
data on such programs--either ground stops or delays--at all the 
airports in our sample, by hour, across the 10 months of our analysis. 
Using the scheduled departure hour, we created two dummy variables 
that were set equal to 1 if the origin or destination airports, 
respectively, had any program in place to slow or stop traffic at the 
hour that a flight was scheduled to depart. We expected that flights 
affected by a ground stop or ground delay program would be associated 
with greater odds of a flight cancellation both on the tarmac and at 
the gate. 

* Airport on-time performance. A final measure that we included in the 
model to capture how well each airport is handling its scheduled 
traffic at a given point in time is the rate of the on-time 
performance. Data for this analysis come from the Aviation System 
Performance Metrics database maintained by FAA. We obtained on-time 
arrival and on-time departure performance information for the airports 
in the model by hour.[Footnote 127] In the model, a variable for the 
on-time departure performance for the origin airport is anchored at 
the hour of scheduled departure. Similarly, another variable is 
constructed for the on-time arrival performance at the destination 
airport. We expected that lower on-time performance measures would 
indicate difficulties in flowing the scheduled traffic and would thus 
be associated with a greater odds of flight cancellation. 

Variables related to airlines and their operations. Some factors that 
might be correlated with the odds of a flight cancellation are related 
to the airline that is operating the flight and how the flight fits 
into that airline's network: 

* Size of airline. Certain airlines may be more inclined to cancel 
flights than other airlines. We separated airlines into three 
categories: the legacy airlines, which are typically the larger 
networked airlines; low-cost airlines, which include Southwest and 
AirTran; and the smaller airlines, such as regional airlines, that 
tend to fly shorter routes with smaller aircraft and often operate 
flights for legacy airlines. We did not include the third airline 
classification in the model; instead we use it as the reference 
category against which the other two categories of airlines are 
compared.[Footnote 128] 

* Airline hub. Many airlines operate a network through which 
particular airports--called hubs--are used for the transfer of traffic 
so that a larger number of routes can be served. Even though our model 
looks at the odds of cancellation for a single leg flight and we do 
not examine itineraries of more than one flight leg, an airline 
considers, when deciding whether to cancel a flight, how its flights 
are interrelated and how passengers transfer among them. If a flight 
takes off from an airport that is a hub for the airline operating that 
flight, we deemed this an origin/hub flight. Likewise, if a flight is 
destined to an airport that the carrier of record states is one of its 
hubs, we designated it as a destination/hub flight. If an airport is a 
hub for an airline, we expect this could affect the decision about 
whether to cancel a flight. 

* Average passengers per flight (on an airline-route basis). This 
variable is designed to take into account the likelihood that airlines 
will attempt to deliver as many passengers as possible to their 
destination and so might be more inclined to cancel flights with fewer 
passengers onboard when circumstances disrupt traffic flow. Because 
data were not available on the number of passengers onboard each 
particular flight, we used the average number of passengers for a 
particular airline on a given route over the course of a month, 
divided by 10. Thus, the results indicate the change in the odds of 
cancellation for each additional 10 passengers on a given airline's 
flight for that route. 

Variable related to the route and flight. The following variables 
provide information about the origin-to-destination route and the 
specific flight. 

* Route distance. Some past research has shown that airlines are less 
likely to cancel longer distance flights. We placed routes in four 
categories according to distance: less than 500 miles, and three 
categories that were more than 750 miles. We did not include the 
flights that fell into the 500 to 750 distance because it is the 
reference category that other distance dummy variables are compared to. 

* Day of the week. Since traffic patterns vary across the days of the 
week, particularly weekdays versus weekend days, we included a dummy 
variable for flights that took place on the weekend. We expected that 
weekend flights will be canceled less often than weekday flights 
because less traffic is scheduled on the weekend making a given set of 
circumstances on the weekend less likely to disrupt traffic on these 
days. 

* Scheduled departure hour. Airlines may be more or less reluctant to 
cancel flights at certain times of the day than at other times. For 
example, canceling early flights may be less problematic because there 
will be more options for rebooking passenger that day than there would 
be later in the day. Additionally, airlines may need to consider where 
an aircraft ends the day in preparation for the next day's traffic, 
and so may prefer not to cancel flights late in the day. We created 
four categories for departure hours: overnight, morning, afternoon, or 
evening. The afternoon category is not included in the model because 
it is the reference group we compare the three other dummy variables 
against. 

Table 17 provides information on the source of data for each of the 
variables. 

Table 17: Variables and Data Sources: 

Variable: Dependent variable: indicator that a flight was canceled; 
Data source: BTS data. 

Variable: Tarmac delay rule dummy variable; 
Data source: n/a. 

Variable: Indicator of length of time on tarmac (used as dummy 
variable and as interaction with tarmac delay dummy variable); 
Data source: BTS data. 

Variable: Dummy variable for congested airports; 
Data source: Identified as seven airports with most delay, based on 
previous GAO report. 

Variable: Endpoint weather variable; 
Data source: National Oceanic and Atmospheric Administration weather 
data and FAA indicators of severity of weather conditions for aviation. 

Variable: Ground stops and ground delays; 
Data source: FAA's Operations Network data. 

Variable: Airport on-time performance; 
Data source: FAA Aviation System Performance Metrics data. 

Variable: Airline size categories; 
Data source: BTS Form 41 data on airline cost structures and previous 
GAO analysis. 

Variable: Airline hub airports; 
Data source: As identified by airlines. 

Variable: Average airline passengers per flight on a route; 
Data source: BTS Form 41 filings. 

Variable: Route distance; 
Data source: BTS data. 

Variable: Day of the week; 
Data source: BTS data. 

Variable: Scheduled departure hour; 
Data source: BTS data. 

Source: GAO. 

[End of table] 

Model Results: 

This section provides results for both the tarmac-cancellation and 
gate-cancellation models. 

Results for Tarmac-Cancellation Model: 

We used output from the logistic regression model for the rule change 
dummy variable and the six dummy variables related to time on the 
tarmac to ascertain the relative odds of flight cancellations before 
and after the implementation of the tarmac rule. Table 18 shows, based 
on the model that controlled for other factors, how the odds of 
cancellation in each tarmac time category in 2010 compared with the 
odds of cancellation for the same tarmac time in 2009--specifically, 
we show the ratio of those odds. In all hour categories of tarmac 
time, the odds of cancellation were greater in 2010 than in 2009 
because all of the odds ratios exceed 1. Moreover, the differential in 
the odds ratio of cancellations across the 2 years increased with the 
time a flight was on the tarmac. For flights that were on the tarmac 
for less than an hour, the odds of a cancellation were about one-third 
higher in 2010 than in 2009. But the longer a flight remained on the 
tarmac the more the relative odds of cancellation were greater in 2010 
than in 2009. For flights with 61 to 120 minutes of tarmac delay, the 
odds ratio rose to 2.14, indicating that the odds of a cancellation 
more than doubled in 2010 compared with 2009, and for flights with 121 
to 180 minutes of tarmac delay, the odds of cancellation more than 
tripled in that same time period. Finally, the odds ratios in table 18 
are very similar to those presented in table 15, indicating that the 
inclusion of key variables to control for other factors did not have 
much effect on our findings related to the tarmac rule. 

Table 18: Odds Ratios Estimates for Variables of Interest in Tarmac- 
Cancellation Model, 2010 versus 2009: 

Variable: 0-60 minutes on tarmac; 
Odds ratio; 2010 hour category compared with same hour in 2009: 
1.31[A]. 

Variable: 61-120 minutes on tarmac; 
Odds ratio; 2010 hour category compared with same hour in 2009: 
2.14[A]. 

Variable: 121-180 minutes on tarmac; 
Odds ratio; 2010 hour category compared with same hour in 2009: 
3.59[A]. 

Source: GAO analysis of DOT data. 

Note: Data for tarmac delays in excess of 3 hours are not included in 
the table because for 2010 the number of such delays was only eight 
and we decided that odds ratios based on such small numbers may not be 
representative. 

[A] Denotes an odds ratio that is significant at the 1 percent level. 
The significance of the coefficients in the models we fit was 
evaluated using a simple Wald test statistic, which is asymptotically 
equivalent to the likelihood-ratio chi-square statistic. We regarded 
as significant all coefficients which yielded a test statistic with an 
associated probability of less than 1 percent, which means that there 
is less than a 1 percent probability of finding an effect (or 
association) as large as the one indicated by the estimated 
coefficient just by chance, or as a result of random fluctuations. 

[End of table] 

Table 19 provides the odds ratios from the logistic regression model 
for all other variables included in the tarmac-cancellation model. 
Some of the key findings are: 

* Flights departing from or destined to an airline's hub airport are 
less likely to be canceled. 

* Flights in evening hours are less likely to be canceled than flights 
departing in the afternoon. 

* Flights of greater than 750 miles are less likely to be canceled 
than flights of 500 to 750 miles. 

* Flights are more likely to be canceled if the departure airport or 
arrival airport is experiencing severe weather at or around the time 
of scheduled departure or arrival, respectively. 

* Flights are more likely to be canceled if a ground stop or ground 
delay was in effect at either the departure airport or the arrival 
airport at the scheduled time of departure. 

Table 44: Logistic Regression Results for Tarmac-Cancellation Model 
and Other Independent Variables: 

Variable: Departure airport is one of seven most congested, compared 
to all other airports; 
Odds ratio estimate: 0.99. 

Variable: Destination airport is one of seven most congested, compared 
to all other airports; 
Odds ratio estimate: 1.26[A]. 

Variable: Legacy airline, compared to smaller airlines; 
Odds ratio estimate: 1.84[A]. 

Variable: Low-cost airline, compared to smaller airlines; 
Odds ratio estimate: 0.24[A]. 

Variable: Weekend day, compared to weekday; 
Odds ratio estimate: 0.86[A]. 

Variable: Scheduled departure in morning hours, compared to afternoon 
hours; 
Odds ratio estimate: 1.04. 

Variable: Scheduled departure in evening hours, compared to afternoon 
hours; 
Odds ratio estimate: 0.51[A]. 

Variable: Scheduled departure in overnight hours, compared to 
afternoon hours; 
Odds ratio estimate: 1.08. 

Variable: Departure airport is a hub for airline; 
Odds ratio estimate: 0.69[A]. 

Variable: Destination airport is a hub for airline; 
Odds ratio estimate: 0.70[A]. 

Variable: Severe weather at departure airport around time of scheduled 
departure; 
Odds ratio estimate: 1.45[A]. 

Variable: Severe weather at destination airport around time of 
scheduled arrival; 
Odds ratio estimate: 2.87[A]. 

Variable: On-time performance, departures at departure airport; 
Odds ratio estimate: 0.73[B]. 

Variable: On-time performance, arrivals at arrival airport; 
Odds ratio estimate: 0.43[A]. 

Variable: Flight is less than 500 miles, compared to flights of 500-
750 miles; 
Odds ratio estimate: 1.09. 

Variable: Flight is 750-1,000 miles, compared to flights of 500-750 
miles; Odds ratio estimate: 0.77[A]. 

Variable: Flight is 1000-1500 miles, compared to flights of 500-750 
miles; 
Odds ratio estimate: 0.71[A]. 

Variable: Flight is 1,500 or more miles, compared to flights of 500-
750 miles; 
Odds ratio estimate: 0.60[A]. 

Variable: Average number of passengers per flight, by airline, route, 
and month (effect is per 10 passengers); 
Odds ratio estimate: 0.92[A]. 

Variable: Ground delay or stop in effect at departure airport around 
departure time; 
Odds ratio estimate: 1.31[A]. 

Variable: Ground delay or stop in effect at destination airport around 
departure time; 
Odds ratio estimate: 1.98[A]. 

Source: GAO analysis of DOT data. 

[A] Denotes an odds ratio that is significant at the 1-percent level. 
The significance of the coefficients in the models we fit was 
evaluated using a simple Wald test statistic, which is asymptotically 
equivalent to the likelihood-ratio chi-square statistic. We regarded 
as significant all coefficients which yielded a test statistic with an 
associated probability of less than 1 percent, which means that there 
is less than a 1 percent probability of finding an effect (or 
association) as large as the one indicated by the estimated 
coefficient just by chance, or as a result of random fluctuations. It 
is not possible, strictly speaking, to characterize a logistic 
regression model in terms of the amount of variance in the dependent 
variable that is explained by the independent variables included in 
the model. We do note, however, that the percentage of canceled and 
noncanceled flights that are correctly classified using this model and 
the independent variables it includes is 86.3 percent. 

[B] Denotes an odds ratio that is significant at the 5-percent level 
according to a Wald test statistic. 

[End of table] 

Results for the Gate-Cancellation Model: 

Table 20 provides the findings for the gate-cancellation model, which 
assesses the likelihood of precancellations, adjusted to account for 
factors other than the tarmac delay rule that may influence the 
incidence of cancellation. One significant finding is that the odds 
ratio for the rule change is substantially greater, when adjusted, 
than indicated by the simple unadjusted odds ratio shown in table 16. 
The model results indicate that the odds of gate cancellations rose by 
24 percent after the rule went into effect, whereas the simple result 
indicated only a 13 percent increase in those odds. This suggests that 
to understand the independent correlation between the tarmac delay 
rule and likelihood of gate cancellation, it is important to control 
for the other factors that are likely correlated with such 
cancellations. 

Findings from the gate-cancellation model suggest: 

* Gate cancellations are more common when a flight is departing from 
or destined to one of the seven most congested airports in the U.S. 

* Gate cancellations are less common for flights scheduled to depart 
in the evening, compared to flights departing in the afternoon. 

* Gate cancellations are more common when severe weather is affecting 
either endpoint airport of a flight at the relevant hour. 

* Gate cancellations are more common for very short flights, compared 
to flights of 500 to 750 miles in distance. 

* Gate cancellations are less common for flights of a more than 750 
miles, compared to flights of 500 to 750 miles. 

* Gate cancellations are more common if a ground delay or ground stop 
was in place at the origin or destination airport at the time of 
scheduled departure. 

* In this case it appears that flights to an airline's hub airport are 
more likely to be canceled. 

Table 20: Logistic Regression Results for Gate-Cancellation Model and 
Other Independent Variables: 

Variable: Rule change dummy; 
Odds ratio estimate: 1.24[A]. 

Variable: Departure airport is one of seven most congested, compared 
to all other airports; 
Odds ratio estimate: 1.27[A]. 

Variable: Destination airport is one of seven most congested, compared 
to all other airports; 
Odds ratio estimate: 1.33[A]. 

Variable: Legacy airline, compared to smaller airlines; 
Odds ratio estimate: 1.57[A]. 

Variable: Low-cost airline, compared to smaller airlines; 
Odds ratio estimate: 0.70[A]. 

Variable: Weekend day, compared to weekday; 
Odds ratio estimate: 0.91[A]. 

Variable: Scheduled departure in morning hours, compared to afternoon 
hours; 
Odds ratio estimate: 1.43[A]. 

Variable: Scheduled departure in evening hours, compared to afternoon 
hours; 
Odds ratio estimate: 0.86[A]. 

Variable: Scheduled departure overnight hours; compared to afternoon 
hours; 
Odds ratio estimate: 1.45[A]. 

Variable: Departure airport is a hub for airline; 
Odds ratio estimate: 1.03. 

Variable: Destination airport is a hub for airline; 
Odds ratio estimate: 1.34[A]. 

Variable: Severe weather at departure airport around time of scheduled 
departure; 
Odds ratio estimate: 1.36[A]. 

Variable: Severe weather at destination airport around time of 
scheduled arrival; 
Odds ratio estimate: 1.30[A]. 

Variable: On-time-performance, departures at departure airport; 
Odds ratio estimate: 0.12[A]. 

Variable: On-time-performance, arrivals at arrival airport; 
Odds ratio estimate: 0.15[A]. 

Variable: Flight is 0-500 miles, compared to flights of 500-750 miles; 
Odds ratio estimate: 1.28[A]. 

Variable: Flight is 750-1000 miles, compared to flights of 500-750 
miles; 
Odds ratio estimate: 0.86[A]. 

Variable: Flight is 1000-1500 miles, compared to flights of 500-750 
miles; 
Odds ratio estimate: 0.88[A]. 

Variable: Flight is 1500 or more miles, compared to flights of 500-750 
miles; 
Odds ratio estimate: 0.57[A]. 

Variable: Average number of passengers per flight, by airline, route, 
and month (effect is per 10 passengers); 
Odds ratio estimate: 0.88[A]. 

Variable: Ground delay or stop in effect at departure airport around 
departure time; 
Odds ratio estimate: 2.14[A]. 

Variable: Ground delay or stop in effect at destination airport around 
departure time; 
Odds ratio estimate: 1.80[A]. 

Source: GAO analysis of DOT data. 

[A] Denotes an odds ratio that is significant at the 1 percent level. 
The significance of the coefficients in the models we fit was 
evaluated using a simple Wald test statistic, which is asymtotically 
equivalent to the likelihood-ratio chi-square statistic. We regarded 
as significant all coefficients which yielded a test statistic with an 
associated probability of less than 1 percent, which means that there 
is less than a 1 percent probability of finding an effect (or 
association) as large as the one indicated by the estimated 
coefficient just by chance, or as a result of random fluctuations. It 
is not possible, strictly speaking, to characterize a logistic 
regression model in terms of the amount of variance in the dependent 
variable that is explained by the independent variables included in 
the model. We do note, however, that the percentage of canceled and 
noncanceled flights that are correctly classified using this model and 
the independent variables it includes is 75.8 percent. 

[End of table] 

Sensitivity Analysis: 

We ran the models using several other specifications, most of which 
involved alternative variable specifications. These runs indicated 
that our findings for the tarmac rule were robust across these 
specifications. Alternatives included the following: 

* Variations on how the specific airlines were grouped. In the base 
case we classified airlines into three categories: legacy airline, low-
cost airline, and all others. In an alternative specification, we 
classified airline as large or small based on the number of 
enplanements. 

* Variations for characterization of origin and destination airports. 
In the base case models, we included dummy variables to indicate that 
the airport (origin or destination) was one of the seven most 
congested airports in the United States. In an alternative 
specification, we used 62 dummy variables to indicate whether the 
airport (origin or destination), was one of the 31 largest airports. 

* Alternative measure for poor weather conditions. In the base case, 
we classified weather at endpoint airports as severe if a weather 
event occurring around the time of the flight would be considered 
highly disruptive to aviation activity. In an alternative 
specification we included both severe and moderately disruptive 
weather conditions. 

* Alternative distance measure. In the base case, we classified 
distance into broad mileage categories. In an alternative 
specification, we entered distance divided by 100 as a continuous 
variable. 

* Elimination of flights that were canceled after a tarmac delay for 
the gate model. For the gate model, we included flights that left the 
gate, even if they were later canceled. We did so because the airlines 
were attempting to get these flights off the ground when they were 
making gate-cancellation decisions, and so we treated these flights as 
nongate cancellations. In one sensitivity run, we eliminated any 
flights that left the gate but were later canceled. 

[End of section] 

Appendix VI: GAO Contact and Staff Acknowledgments: 

GAO Contact: 

Susan Fleming, (202) 512-2834 or flemings@gao.gov: 

Staff Acknowledgments: 

In addition to the contact named above, Paul Aussendorf, Assistant 
Director; Amy Abramowitz; Kyle Browning; Lauren Calhoun; Anne Doré; 
Grant Mallie; Michael Mgebroff; Sara Ann Moessbauer; Josh Ormond; and 
Melissa Swearingen made key contributions to this report. 

[End of section] 

Footnotes: 

[1] See Senate Joint Economic Committee, Your Flight Has Been Delayed 
Again: Flight Delays Cost Passengers, Airline and the U.S. Economy 
Billions (Washington, D.C.: May 2008), and M. Ball, C. Barnhart, M. 
Dresner, et al, Total Delay Impact Study A Comprehensive Assessment of 
the Costs and Impacts of Flight Delay in the United States, National 
Center of Excellence for Aviation Operations Research, Federal 
Aviation Administration (November 2010). This latter study estimated 
that the total cost of all U.S. air transportation delays in 2007 was 
$31.2 billion, with the $16.7 billion passenger component based on the 
passenger time lost due to schedule buffer, delayed flights, flight 
cancellations, and missed connections. 

[2] According to the U.S. Department of Transportation, a "tarmac 
delay means the holding of an aircraft on the ground either before 
taking off or after landing with no opportunity for its passengers to 
deplane." 

[3] In the EU, the European Commission, whose mission is to promote 
the general interest of the EU, initiates the legislative process by 
drafting specific pieces of legislation and proposing them to the 
Council of the European Union and European Parliament who together 
serve as the EU's legislative branch. Under the EU's co-decision 
procedure, both the Council of the EU and the European Parliament must 
approve legislation in order to enact a law. The European Union 
currently has 27 member states. 

[4] Regulation (EC) 261/2004, art. 3, 2004 O.J. (L 46/1). The 
regulation was passed by the European Parliament and the Council of 
the European Union in 2004, but came into force in February, 2005. 

[5] Throughout this report, we refer to the "tarmac delay rule," which 
is one component (contingency plans for lengthy tarmac delays) of the 
Enhancing Airline Passenger Protections Final Rule. 74 Fed. Reg. 68983 
(Dec. 30, 2009). Unless otherwise stated, reference to the "tarmac 
delay rule" refers to this single component of the rule. 

[6] The modifier "legacy" derives from the fact that these airlines 
were operating when the industry deregulated in 1978. Although the 
airline industry is now largely free of economic regulation, it 
remains regulated in other areas, most notably safety, security, and 
operating standards. 

[7] Many regional airline flights are operated under a fee-for-service 
arrangement whereby the airline marketing the flight has decision- 
making control over most of the inventory of the airline operating the 
flight, including the decision to cancel flights. 

[8] Commercial service airports are defined by 49 U.S.C. § 47102 as 
public airports that the Secretary of Transportation determines have 
2,500 passenger boardings (enplanements) each year and receive 
scheduled passenger aircraft service. 

[9] FAA divides commercial service airports into primary airports 
(enplaning more than 10,000 passengers annually) and other commercial 
service airports. Among primary airports, "nonhub" airports enplane 
fewer than 0.05 percent of systemwide passengers, "small" hub airports 
enplane at least 0.05 percent but fewer than 0.25 percent of 
systemwide passengers, "medium" hub airports enplane at least 0.25 
percent but fewer than 1 percent of systemwide passengers, and "large" 
hub airports enplane at least 1 percent of systemwide passengers. 49 
U.S.C. § 47102. 

[10] FAA's Operations Network provides information on which airports 
delays were attributed to--that is, which facility instituted a 
traffic management initiative that resulted in flights being delayed. 
In 2010, we reported that seven airports--Newark Liberty 
International, New York John F. Kennedy International, New York 
LaGuardia, Atlanta Hartsfield International, Philadelphia 
International, Chicago O'Hare International, and San Francisco 
International--were the main drivers of departure delay across the 
system and that these airports accounted for about 80 percent of 
departure delays at airports across the national airspace system. See 
GAO, National Airspace System: Setting On-Time Performance Targets at 
Congested Airports Could Help Focus FAA's Actions, [hyperlink, 
http://www.gao.gov/products/GAO-10-542] (Washington, D.C.: May 26, 
2010). 

[11] [hyperlink, http://www.gao.gov/products/GAO-10-542]; National 
Airspace System: Long-Term Capacity Planning Needed Despite Recent 
Reduction in Flight Delays, [hyperlink, 
http://www.gao.gov/products/GAO-02-185] (Washington, D.C.: Dec. 14, 
2001); and GAO, Air Traffic Control: Role of FAA's Modernization 
Program in Reducing Delays and Congestion, [hyperlink, 
http://www.gao.gov/products/GAO-01-725T] (Washington, D.C.: May 10, 
2001). 

[12] See Bengi Manley and Lance Sherry, The Impact of Ground Delay 
Program (GDP) Rationing Rules on Passenger and Airline Equity, Center 
for Air Transportation Systems Research, George Mason University 
(2008); Nicholas G. Rupp, An Investigation Into the Determinants of 
Flight Cancellations, East Carolina University (2005); and Zalman 
Shavell, The Effects of Schedule Disruptions on the Economics of 
Airline Operations, Mitre Corporation (2000). 

[13] [hyperlink, http://www.gao.gov/products/GAO-10-542]. 

[14] [hyperlink, http://www.gao.gov/products/GAO-10-542]. 

[15] M. Ball, C. Barnhart, M. Dresner, et al, Total Delay Impact Study 
A Comprehensive Assessment of the Costs and Impacts of Flight Delay in 
the United States, National Center of Excellence for Aviation 
Operations Research, FAA (November 2010). 

[16] 14 C.F.R. part 250. 

[17] Though an Airline Passenger Bill of Rights Act was introduced in 
1999 to provide "enhanced protections for airline passengers," it did 
not come to a vote. Airline Passenger Bill of Rights Act of 1999, H.R. 
700, 106th Cong. (1999). 

[18] Wendell H. Ford Aviation Investment and Reform Act for the 21st 
Century (AIR-21), Pub. L. No. 106-181, § 224, 114 Stat. 61, 103 (2000). 

[19] Airline Passenger Bill of Rights Act, H.R. 1734, 107th Cong. 
(2001); Airline Passenger Bill of Rights Act of 2007, S.678, 110th 
Cong. (2007); Airline Passenger Bill of Rights Act of 2009, S.213, 
111th Cong. (2009); Airline Passenger Bill of Rights Act of 2011, H.R. 
729, 112th Cong. (2011). 

[20] 73 Fed. Reg. 21026 (Apr. 18, 2008). 

[21] 74 Fed. Reg. 68983 (Dec. 30, 2009). 

[22] For international flights that depart from or arrive at a U.S. 
airport, a contingency plan must provide that an airline will not 
permit an aircraft to remain on the tarmac for more than a set number 
of hours, as determined by the airline, before allowing passengers to 
deplane. The exceptions for domestic flights apply to international 
flights, as well. 

[23] 74 Fed. Reg. 68983 (Dec. 30, 2009), codified at 14 C.F.R. § 
259.4. This rule applies to all certificated and commuter air carriers 
(i.e., U.S. airlines) that operate scheduled passenger service or 
public charter service using any aircraft originally designed to have 
a passenger capacity of 30 or more seats. These requirements also only 
apply to flights at large-and medium-hub airports. 

[24] 49 U.S.C. § 41712. 

[25] 14 C.F.R. § 383.2(a) prescribes penalties for civil violations, 
including those under 49 U.S.C. § 41712. 

[26] 79 Fed. Reg. 23110 (Apr. 25, 2011). 

[27] On July 20, 2011, DOT extended the effective date of certain 
provisions of the rule from August 23, 2011 to January 24, 2012. 
Specifically, DOT extended the effective date of requirements 
pertaining to full fare advertising, specific baggage fee disclosures, 
post-purchase price increases, flight status notifications (e.g., 
notifications to passengers in the event of delays, cancellations, or 
diversions), and holding a reservation without payment. DOT did not 
extend the effective date for the tarmac delay provisions. 76 Fed. 
Reg. 45181 (July 28, 2011). GAO, Commercial Aviation: Consumers Could 
Benefit from Better Information about Airline-Imposed Fees and 
Refundability of Government-Imposed Taxes and Fees, [hyperlink, 
http://www.gao.gov/products/GAO-10-785] (Washington, D.C.: July 14, 
2010). 

[28] EU airlines departing outside of the EU but bound for an EU 
airport are required to adhere to EU regulations, except where the 
country of departure has provided benefits or compensation or 
assistance. Regulation (EC) 261/2004, art. 3, 2004 O.J. (L 46/1). 

[29] Additionally, these three regions also prescribe requirements for 
what must addressed in an airline contract of carriage. For example, 
Canada's Air Transportation Regulations require airlines to clearly 
state in their contracts of carriage their policies related to the 
treatment of passengers, including their policies related to flight 
delays, cancellations, and denied boarding. Air Transportation 
Regulations SOR/88-58, Part V, Div. I, § 107(1)(n) (Can). 

[30] According to DOT, many provisions of the contracts of carriage 
are also filed in the airlines' tariffs with DOT and with their 
governments. 

[31] In addition, in the United States, regulations require certain 
U.S. and foreign airlines to develop customer service plans to post on-
time performance data for each flight on their Web sites. Airlines 
must state in these customer service plans certain commitments to 
passengers, such as the commitment to reimburse for any fee charged to 
transport a bag that is lost, notify customers of flight disruptions 
within 30 minutes of the airline's becoming aware of the disruption, 
and handle bumped passengers with fairness and consistency. 

[32] Convention for the Unification of Certain Rules for International 
Carriage by Air (Montreal Convention), ch.3, art. 19, May 28, 1999 
(entered into force on Nov. 4, 2003), reprinted in S. Treaty Doc. 
No.106-45. The Montreal Convention also limits airlines' liability for 
delays to 4150 Special Drawing Rights (or $6,658.87 as of July 22, 
2011) per passenger. Montreal Convention, art. 22. 

[33] FlightStats is an operating platform, owned and operated by 
Conducive Technology, which records flight performance information. 
This database includes more flight performance information than DOT's 
Airline Service Quality Performance System (ASQP) database. For 
example, the data we obtained included performance information for 
about 98 percent of U.S. scheduled passenger flights in 2010 from 
airports considered primary for fiscal year 2009, excluding airports 
in U.S. territories. ASQP data included about 77 percent of flights 
from those airports. In general, the ASQP data were more complete for 
airports in larger communities. For example, only about 45 percent of 
all flights from airports in rural communities were captured by ASQP. 

[34] Specifically, we grouped all airports considered primary for 
fiscal year 2009, excluding airports in U.S. territories, into four 
categories based on population: greater than or equal to 1 million 
(large metropolitan), 250,000 to 999,999 (midsized metropolitan), 
50,000 to 249,999 (small metropolitan), and fewer than 50,000 (rural). 
This approach controls for the fact that some small or medium airports-
-generally secondary airports such as Hobby Airport in Houston--are 
actually in large metropolitan regions. Using these categories, in 
2010, we examined data from 76 airports in large metropolitan 
communities, 99 in midsized metropolitan communities, 117 in small 
metropolitan communities, and 52 in rural communities. We excluded 
commercial service, nonprimary airports because they handle fewer than 
10,000 enplanements annually and therefore are not considered airports 
that provide connectivity to the national airspace system. 

[35] A flight is "diverted" if it lands at an airport other than its 
scheduled destination because of extreme weather or security concerns, 
for example. 

[36] This 8 percent figure for 2010 represented 6,844 departure 
cancellations and 932 departure diversions from airports in rural 
communities. 

[37] Sherry, Lance, Passenger Trip Delay Statistics for 2010, Center 
for Air Transportation Systems Research at George Mason University. To 
be presented at the Transportation Research Board 91ST Annual Meeting 
(January 2012). 

[38] Lance Sherry, Passenger Trip Delay Statistics for 2010. DOT also 
reports average delay times for aircraft. Since 2005, the average 
delay per delayed aircraft arrival is about 55 minutes. 

[39] 14 C.F.R. part 234. 

[40] Departure data also showed differences between FlightStats and 
DOT data, with FlightStats showing a slightly higher percentage of 
flights from airports in rural communities delayed, canceled, or 
diverted. However, FlightStats showed lower percentages of flights 
from airports in large, midsized, and small communities delayed, 
canceled, or diverted than did DOT data. 

[41] Based on data for all reported flights, DOT reporting airlines' 
flights were delayed 19.54 percent, canceled 1.59 percent, and 
diverted 0.16 percent of the time. Nonreporting airlines were delayed 
20.27 percent, canceled 2.48 percent, and diverted 0.25 percent of the 
time. 

[42] Zinser, Todd, Report on the Audit of Small Community Aviation 
Delays and Cancellations, Report No. CR-2006-049 (May 19, 2006). 

[43] N. Rupp and G. Holmes, An Investigation into the Determinants of 
Flight Cancellations. Also see, Jing Xiong, Revealed Preference of 
Airlines' Behavior under Air Traffic Management Initiatives, 
dissertation (2010). 

[44] FlightStats uses flight schedules to track the actual performance 
of flights based on data from various airport and on-line sources. 
This generates extensive, real-time data on flights, which is then 
archived in its database. After reviewing the data and supporting 
documentation, as well as discussions with relevant officials, we 
determined that FlightStats data were sufficiently reliable for the 
purposes of this report. 

[45] The purpose of this information is to provide consumers with 
information on airlines' quality of service. See 14 C.F.R. § 234.1. 

[46] DOT data include information on tarmac delays of more than 3 
hours for all domestic airlines that handle at least 1 percent of all 
domestic scheduled passenger service revenue. Since DOT determines 
annually which airlines meet the threshold and therefore must report 
flight performance data, the number of airlines required to report 
varies. In 2010, 16 airlines were required to report and 2 reported 
voluntarily. Since October 2008, DOT has required airlines to submit 
additional tarmac delay statistics. As of August 23, 2011, covered 
airlines, both United States and foreign, are required under 14 C.F.R. 
§ 244.2 to report all passenger operations that experience a tarmac 
time of more than 3 hours at a U.S. airport, in a form as set forth in 
regulation. A covered airline includes all U.S. certificated air 
carriers, U.S. commuter airlines, and foreign airlines that operate 
passenger service to or from a U.S. airport with at least one aircraft 
that has an original manufacturer's design capacity of 30 or more 
seats. See 76 Fed. Reg. 23110, 23161 (Apr. 25, 2011). 

[47] Starting in 2008, DOT began monitoring tarmac delays more 
closely, requiring reporting airlines to submit data on all tarmac 
delays. Prior to October 2008, airlines reported data on tarmac delays 
that occurred during taxi-out or taxi-in. Since October 2008, airlines 
have been required to submit long tarmac delay statistics for three 
additional categories: flights that are canceled after the tarmac 
delay, flights that return to the gate after the tarmac delay before 
taking off, and flights that experience extended tarmac delays during 
taxi-in at a diversion airport. In 2009, of the 868 long tarmac 
delays, one-third (283 flights) were captured in these new categories. 

[48] For the purposes of this report we consider the summer season to 
run from May through September. 

[49] Since 2003, airlines have reported the cause of delay to DOT in 
one of five broad categories: late-arriving aircraft, airline, 
national airspace system, extreme weather, and security. Tarmac delays 
of more than 3 hours during both taxi-out and taxi-in are usually 
officially attributed by airlines to issues with the national airspace 
system. For example, since 2004, 86 percent of such taxi-out delays 
were attributed to the national airspace system, according to DOT 
data. The extent to which delays attributed to the national airspace 
system are related to weather events is unknown, since this reporting 
category includes delays caused by air traffic control issues, weather 
that slows down operations at an airport, or other ground congestion. 
Delays during taxi-in may also occur at diversion airports when 
Transportation Security Administration or Customs and Border 
Protection officials are not available at airports where passengers 
are arriving, according to one airline association. For example, a 
regional airline flight from Houston to Minneapolis that was diverted 
to Rochester, Minnesota, in the summer of 2009, sat on the tarmac in 
Rochester for more than 5 hours because there was severe weather and 
confusion over the Transportation Security Administration's after 
hours operating procedures. DOT fined Continental Airlines, which had 
contracted the ExpressJet flight, and ExpressJet each $50,000 for this 
incident. In addition, DOT assessed a civil penalty of $75,000 against 
Mesaba Airlines, which provided voluntary ground handling to 
ExpressJet, for providing inaccurate information to ExpressJet about 
deplaning passengers, which was found to be an unfair and deceptive 
practice in violation of 49 U.S.C. § 41712. DOT Order 2009-11-16 (Nov. 
24, 2009). 

[50] In 2010 we reported that, according to FAA's Operations Network 
data, these seven airports--Newark Liberty International, New York 
John F. Kennedy International, New York LaGuardia, Atlanta Hartsfield 
International, Philadelphia International, Chicago O'Hare 
International, and San Francisco International--were the main drivers 
of departure delay across the system, and that these airports 
accounted for about 80 percent of departure delays at airports across 
the national airspace system. See [hyperlink, 
http://www.gao.gov/products/GAO-10-542]. 

[51] Enhancing Airline Passenger Protections, 74 Fed. Reg. 68983 (Dec. 
30, 2009). 

[52] 14 C.F.R. § 259.4(b). As noted previously, as of August 23, 2011, 
international flights of U.S. and foreign carriers are subject to a 4- 
hour time limit on tarmac delays, subject to exceptions for safety, 
security, and disruption of airport operations. 

[53] 14 C.F.R. § 383.2(a) prescribes penalties for civil violations, 
including those under 49 U.S.C. § 41712. The term "violation" is not 
defined in statute or regulation. 

[54] Over these same time periods, tarmac delays of more than 4 hours 
went from 105 to 0. 

[55] To date, two airlines have been fined in connection with the 
tarmac delay rule, but not for exceeding the 3-hour limit. United 
Airlines and Pinnacle Airlines were fined $12,000 and $10,000, 
respectively, in September 2010 for misreporting tarmac delays. Both 
airlines reported incurring delays of more than 3 hours to DOT on 
Bureau of Transportation Statistics Form 234 (On-Time Flight 
Performance Report). However, after an investigation was initiated by 
DOT, the department, or United Airlines in their respective situation, 
determined that they had made an erroneous report and the delay was 
under 3 hours. The airlines were fined for reporting inaccurate data. 
DOT Orders 2010-9-22, 2010-9-11. As of the spring 2011, DOT was also 
investigating potential violations of other aspects of the rule 
including the requirement to provide food and water service by 2 
hours, cabin temperature, and the availability of lavatory services. 

[56] Of the remaining flights, three were able to take off shortly 
after 3 hours, three returned to the gate prior to takeoff, and two 
were at a diverted airport and able to reach the gate. 

[57] DOT officials told us that, although they are not required to, 
they could issue guidance on their penalty structure as it pertains to 
the tarmac delay rule, but have chosen not to in order to maintain 
flexibility under their current authority. 

[58] We used DOT's ASQP flight performance data because FlightStats 
data are not sufficiently detailed for the analysis we present in this 
section. Further, though DOT data are more limited for smaller 
airlines and airports than FlightStats, the tarmac rule implemented on 
April 30, 2010, applied only to flights at large-and medium-hub 
airports. However, the April 2011 rule, effective August 23, 2011, 
expands the rule to small and nonhub airports. 

[59] According to DOT data, scheduled flights only declined by 0.1 
percent (or 3,167 flights) from 2009 to 2010. 

[60] Overall, fewer flights were delayed on the tarmac for more than 1 
hour in 2010 than were delayed in 2009, although the cancellation rate 
was higher for the 2010 flights. Specifically, from May through 
September 2010, 17,763 flights sat on the tarmac for more than 1 hour, 
compared with 22,364 during the same time period in 2009. 

[61] DOT limited its analysis to cancellations of flights that were 
delayed on the tarmac at least 2 hours because "they are virtually 
certain to be directly related to a lengthy tarmac delay." Using that 
criterion, in its December 2009 regulatory analysis of the final rule, 
DOT estimated that the rule would result in 41 additional canceled 
flights per year, affecting 3,176 passengers. According to DOT, the 
impact of additional cancellations on passengers varies. For 
passengers who boarded a flight before it is canceled, the majority 
will wait longer for another flight the same day, while others will 
return to the airport the following day. 

[62] We also heard from some airlines that they have diverted more 
flights to avoid congested airports that may lead to long tarmac 
delays during taxi-in for those flights. According to officials we 
spoke with, this has included re-routing flights away from hub 
airports and "landing short" of their destination at an airport where 
they have resources to accommodate the diverted plane. Furthermore, to 
avoid challenges at the diversion airport, at least some airlines have 
altered where they divert to. Prior to the rule, airlines might have 
just landed at the closest airport. Now, however, they are being more 
proactive, choosing to land at airports where they have supplies 
(i.e., gate space, employees, and equipment) and are more equipped to 
handle the traffic. Since the implementation of the rule, arrival 
diversions have increased almost 5 percent from 7,272 to 7,617, 
according to DOT data for the summers of 2009 and 2010, when flight 
traffic levels were similar. However, this increase cannot necessarily 
be attributed to the implementation of the tarmac delay rule. 

[63] A logistic regression (or logit method) provides an indication of 
which independent variables are correlated with the dependent 
variable--which in this case, is the incidence of a flight 
cancellation. Moreover, it provides this measure of correlation 
independent of the effects of the other independent variables included 
in the model. It is important to note, however, that this type of 
statistical method only suggests correlations between variables and 
not causation. That is, our findings do not provide an indication that 
any of the independent variables we included in the model actually 
caused (or did not cause) cancellations, but only how those variables 
are correlated with the incidence of cancellations. 

[64] Both models analyze flights between 70 airports in the United 
States and Puerto Rico. The FAA Aviation System Performance Metrics 
database includes performance data on operations at 77 airports. Our 
analysis included domestic flights operated by DOT reporting airlines 
to and from these airports, except for three in Alaska and Hawaii (Ted 
Stevens Anchorage International Airport, Honolulu International 
Airport, and Kahului Airport) which were not included and four (Gary 
Chicago International Airport, Greater Rockford Airport, Teterboro 
Airport, and Van Nuys Airport) that had no reported flights to or from 
the other 70 airports during the months of our analysis. The 70 
airports used in our analysis mostly overlap with the large-and medium-
hub airports at which flights were required to comply with the tarmac 
delay rule in 2010. 

[65] Since our models used data only from 2009 and 2010, we did not 
need to exclude any particular flight records due to data reporting 
issues because, as noted earlier, DOT enhanced its tarmac delay data 
collection procedures in October 2008, improving its data reliability. 

[66] For example, weather events and ground delay programs at either 
the origin or destination airport were associated with a greater 
incidence of cancellation. Much like previous academic work on 
cancellations, our results also showed that the likelihood of 
cancellation decreases as the length of the flight increases. 

[67] As discussed later in this report, all four of Canada's major 
airlines have added these provisions to their contracts of carriage in 
response to this initiative. 

[68] Regulation (EC) 261/2004, 2004 O.J. (L 46/1). 

[69] Regulation (EC) 261/2004 applies to the following: (1) all 
flights departing an EU signatory member states' airport (regardless 
of the destination) and (2) all EU airline flights departing outside 
the EU (a third country) into the EU unless the country of departure 
has provided benefits or compensation or assistance. Regulation (EC) 
261/2004, art. 3, 2004 O.J. (L 46/1). This regulation applies to 
operating airlines, but the liability falls upon the airline which is 
contractually obligated to the passenger. Under article (3)(5), when 
an operating airline which has no contract with the passenger performs 
obligations under this regulation, it shall be regarded as doing so on 
behalf of the person having a contract with that passenger. 

[70] Regulation (EC) 261/2004, articles 6 and 9, 2004 O.J. (L 46/1). 
According to a recent European Commission report of delay data 
voluntarily provided by airlines, on average, less than 1.2 percent of 
all flights departing from and arriving in the EU between 2006 and 
2009 potentially fall under the scope of their passenger protections 
regarding long delays (i.e., where flights are delayed by at least 2 
hours). 

[71] Regulation (EC) 261/2004, articles 6(1)(iii) and 8(1)(a), 2004 
O.J. (L 46/1). But see, infra, C-402/07 and C-432/07, Sturgeon v. 
Condor Flugdienst GmbH Böck, Lepuschitz v. Air France SA, 2009 E.C.R. 
I-10923. 

[72] Regulation (EC) 261/2004, art. 14, 2004 O.J. (L 46/1). 

[73] As mentioned earlier, passengers who experience a long delay on 
the airport tarmac in the United States are entitled to certain care, 
such as food and water no later than 2 hours, and the assurance a 
plane will not remain on the tarmac greater than 3 hours. 14 C.F.R. 
part 259. Additionally, the Montreal Convention may also be applicable 
when international passengers are delayed, allowing passengers to take 
legal action against an airline for damages. Convention for the 
Unification of Certain Rules for International Carriage by Air 
(Montreal Convention), ch.3, art. 19, May 28, 1999 (entered into force 
on Nov. 4, 2003), reprinted in S. Treaty Doc. No.106-45. Furthermore, 
Canadian airlines are required to address the "failure to operate on 
schedule" in their contract of carriage. Air Transportation 
Regulations SOR/88-58, Part V, Div. I, § 107(1)(n)(vi) (Can). Finally, 
DOT officials told us that they can, in certain circumstances, take 
enforcement actions and issue fines against airlines unless the 
airline provides passengers with refunds after cancellations and 
extensive delays. 

[74] Rerouting shall be provided under comparable transport 
conditions, to the passenger's final destination at the earliest 
opportunity; or, under comparable transport conditions, to the 
passenger's final destination at a later date at the passenger's 
convenience, subject to the availability of seats. Regulation (EC) 
261/2004, art. 8, 2004 O.J. (L 46/1). The rerouting does not 
necessarily need to be operated by the airline the passenger booked 
with. See, Information Document of the Directorate-General for Energy 
and Transport: Answers to Questions on the Application of Regulation 
(EC) 261/2004, February 17, 2008. 

[75] Regulation (EC) 261/2004, articles 5 and 8, 2004 O.J. (L 46/1). 
Reimbursement must be within seven days and must provide the full cost 
of the ticket at the price at which it was bought, for the part(s) of 
the journey not made, and for the part(s) of the journey made if the 
flight is no longer serving any purpose in relation to the passenger's 
original travel plans. Regulation (EC) 261/2004, art. 8(1)(a), 2004 
O.J. (L 46/1). 

[76] The operator may reduce the compensation by 50 percent if the 
arrival time on the reroute does not exceed the originally scheduled 
arrival time by (1) 2 hours for all flights 1,500 kilometers (km) or 
less, (2) by 3 hours for all intra-community flights more than 1,500 
km and all other flights between 1,500 km and 3,500 km, and (3) by 4 
hours for all other flights. Regulation (EC) 261/2004, art. 7(2), 2004 
O.J. (L 46/1). 

[77] Regulation (EC) 261/2004, art. 5(3), 2004 O.J. (L 46/1). See also 
C-549/07, Wallentin-Herman v. Alitalia--Linee Aeree Italiane SpA, 2007 
E.C.R. I-nyr. 

[78] Regulation (EC) 261/2004, art. 14, 2004 O.J. (L 46/1). According 
to a recent Commission report of delay data voluntarily provided by 
airlines, on average, about 0.5 percent of scheduled flights in Europe 
between 2006 and 2009 were canceled and potentially fall under the 
scope of their passenger protections regarding cancellations. 

[79] Consumers have a private right of action for refunds under the 
Consumer Credit Protection Act, 15 U.S.C. § 1601 et seq.; DOT has 
codified these requirements at 14 C.F.R. part 374. Additionally, 
according to officials at DOT, it can take enforcement action against 
airlines, under 49 U.S.C. § 41712, for the refusal to issue refunds 
for the purchase price of a ticket, within a certain number of days, 
to passengers who wish to cancel their trip as a result of a flight 
cancellation or significant schedule change (for example, flight 
delay). 

[80] Cancellations and refund policies, however, are required to be 
addressed in an airline's contract of carriage. Air Transportation 
Regulations SOR/88-58, Part V, Div. I, § 107(1)(n)(vi), (vii), 122(c) 
(Can). 

[81] Canadian regulations require airlines to set forth policies 
related to compensation for denial of boarding in their contracts of 
carriage. Air Transportation Regulations SOR/88-58, Part V, Div. I, § 
107(1)(n)(iii), (vii), 122(c) (Can). 

[82] 14 C.F.R. § 250.2b; Regulation (EC) 261/2004, art. 4, 2004 O.J. 
(L 46/1). Under the EU regulation, passengers who volunteer to 
surrender their reservations must also be offered the choice between 
reimbursement and a return flight to the first point of departure or 
rerouting to their final destination at the earliest opportunity. 

[83] Boarding priority factors may include, but are not limited to, 
the following: a passenger's time of check-in, whether a passenger has 
a seat assignment before reaching the gate for airlines that assign 
seats, the fare paid by a passenger, a passenger's frequent flyer 
status, and a passenger's disability or status as an unaccompanied 
minor. 14 C.F.R. § 250.3. 

[84] The factors that determine the amount of financial compensation 
are different in the EU and the U.S. In the EU, compensation depends 
on the time passengers reach their final destination after being re-
routed and the distance of the flight, and in the United States, it 
depends on the time passengers are re-routed and whether it is a 
domestic or international flight. Regulation (EC) 261/2004, articles 4 
and 7, 2004 O.J. (L 46/1); 14 C.F.R. § 250.5. Passengers who are 
involuntarily denied boarding will not be entitled to compensation if 
they are offered alternative transportation that, at the time the 
arrangement is made, is planned to arrive at the first stop-over, or 
if none, the final destination, not later than 1 hour after the 
original flight's arrival time. U.S. airlines may offer free or 
reduced rate air transportation in lieu of cash if the value is equal 
to or greater than the cash payment otherwise required and the airline 
informs the passenger of the amount of cash compensation that would 
otherwise be due and that the passenger may decline the transportation 
benefit and receive the cash payment. 14 C.F.R. § 250.5(b). 
Additionally, in accordance with DOT's Final Rule on Enhancing Airline 
Passenger Protections, as of August 23, 2011, the airline must also 
disclose all material restrictions on airline travel vouchers that may 
apply. 76 Fed. Reg. 23110 (Apr. 25, 2011), at 49 C.F.R. § 250.5(c)(3). 

[85] Regulation (EC) 261/2004, articles 8 and 9, 2004 O.J. (L 46/1). 

[86] Regulation (EC) 261/2004, art. 14, 2004 O.J. (L 46/1); 14 C.F.R. 
§ 250.9. Additionally, in accordance with DOT's Final Rule on 
Enhancing Airline Passenger Protections, as of August 23, 2011, the 
airline must also provide verbal notification of such rights. 76 Fed. 
Reg. 23110 (Apr. 25, 2011). Furthermore, although not required, the 
four major Canadian airlines include in their contracts of carriage 
similar denied boarding procedures as in the United States and the EU. 

[87] Officials from the Canadian Transportation Agency identified the 
four major Canadian airlines as Air Canada, WestJet, Air Transat, and 
Air Canada Jazz. 

[88] The Code of Conduct also specifies that airlines should provide 
refreshments to passengers who experience a delay while on the tarmac, 
if it is safe, practical, and timely to do so, and the option to 
deplane after 90 minutes if circumstances permit. 

[89] Additionally, several airline officials told us that they do not 
document their overall costs for complying with passenger service 
requirements. 

[90] Steer Davies Gleave, Evaluation of Regulation 261/2004, European 
Commission, Directorate-General Energy and Transport (London, UK, 
February 2010). 

[91] See GAO, Airline Deregulation: Reregulating the Airline Industry 
Would Likely Reverse Consumer Benefits and Not Save Airline Pensions, 
[hyperlink, http://www.gao.gov/products/GAO-06-630] (Washington, D.C.: 
June 9, 2006). 

[92] During the last 5 years, flight cancellations have generally been 
less frequent in the EU than in the United States. According to 
Commission estimates, flight cancellations comprised about 0.5 percent 
of all flights in Europe from 2006 through 2009. According to DOT 
data, canceled flights in the United States ranged from about 1.4 
percent to 2.1 percent of U.S. flights during the same period. The EC 
reported that flight cancellations in Europe increased to about 2.3 
percent of all flights during 2010 primarily because of unfavorable 
flight conditions caused by the eruption of the Eyjafjallajökull 
volcano in Iceland. 

[93] Increases in required compensation for passengers involuntarily 
denied boarding could motivate airlines to be more aggressive when 
seeking volunteers for denied boarding, such as increasing the value 
of vouchers offered to passengers that willingly deplane, since they 
may be able to offer these volunteers compensation that is less than 
the amount required for passengers involuntarily denied boarding. 

[94] Officials of one low-cost U.S. airline, though, did tell us that 
the cost associated with the 2008 increase in denied boarding 
compensation forced the airline to reduce overbooking levels by 
approximately 25 percent. 

[95] Prior to implementation of the current EU requirements 
(Regulation (EC) 261/2004), EU law required airlines to provide 
passengers denied boarding on flights of 3,500 kilometers or less with 
150 euros and passengers denied boarding on flights of more than 3,500 
kilometers with 300 euros. Regulation (EC) 261/2004 increased the 
required denied boarding compensation to 250 euros for flights of 
1,500 kilometers or less, 400 euros for flights of more than 1,500 
kilometers but less than 3,500 kilometers, and 600 euros for flights 
of more than 3,500 kilometers. 

[96] Officials from enforcement bodies we spoke with in all three 
regions told us they attempt to resolve passenger complaints with the 
airline informally before conducting a formal investigation. 

[97] DOT officials told us that they closed 717 passenger complaint 
cases in 2009 and 828 cases in 2010. As of May 26, 2011, they have 
closed 328 cases and 454 cases remain open. In 2009-2010, CTA received 
a total of 642 air travel complaints for processing through its 
dispute resolution processes, 599 for informal facilitation and 43 for 
formal adjudication. 

[98] Officials at the CTA told us that enforcement staff can impose 
financial penalties against an airline or take administrative actions 
against the airline, including issuing formal reprimands, cease and 
desist orders, license suspensions, and license cancellations. CTA can 
also order an airline to modify their contract of carriage and if the 
airline has failed to apply its contract of carriage correctly, they 
can award a passenger their out-of-pocket expenses as a result of the 
airline's failure to apply the contract of carriage. They may also 
order appropriate corrective measures pursuant to regulation. Air 
Transportation Regulations SOR/88-58, Part V, Div. II, § 113.1(a) 
(Can). 

[99] According to DOT officials, these proactive investigations began 
in 2008 and involve on-site examination of airlines' compliance with 
DOT's air travel consumer protection regulations covering advertising, 
refunds, carriage of passengers with disabilities, baggage, and 
oversales, as well as to review the airline's customer service 
commitments and manuals and training materials relevant to DOT's 
consumer protection requirements. DOT officials said they conduct 
about six such investigations each year. 

[100] Steer Davies Gleave, Evaluation of Regulation 261/2004. 

[101] European Commission, Communication From the Commission to the 
European Parliament and the Council (April 2011). 

[102] "Extraordinary circumstance" is not defined in Regulation (EC) 
261/2004. The regulation exempts an airline from the obligation to pay 
compensation in the event of a cancellation if the airline can prove 
that the cancellation is caused by extraordinary circumstances that 
could not have been avoided even if all reasonable measures had been 
taken. Regulation (EC) 261/2004, art. 5(3), 2004 O.J. (L 46/1). In 
Wallentin-Herman, the ECJ defined extraordinary circumstances as 
events which by their nature are not inherent in the normal exercise 
of the activity of the airline and are beyond its actual control. 
Wallentin-Herman v. Alitalia--Linee Aeree Italiane SpA, 2007 E.C.R. I-
nyr. 

[103] Wallentin-Herman v. Alitalia-Linee Aeree Italiane SpA, 2007 
E.C.R. I-nyr. 

[104] Sturgeon v. Condor Flugdienst GmbH Böck, Lepuschitz v. Air 
France SA, 2009 E.C.R. I-10923. 

[105] TUI Travel Plc, British Airways Plc, Easyjet Airline Company Ltd 
and International Air Transport Association v. The Civil Aviation 
Authority, Case CO/6569/2010. 

[106] According to Commission officials, passengers in the UK may 
still submit a complaint related to the ECJ ruling through the court 
system. 

[107] The Commission does strive to ensure that the application of EU 
regulations is harmonized so that passengers are provided with equal 
treatment across the EU. In order to create harmonization, the EU 
encourages enforcement bodies to discuss issues and standardize their 
practices through meetings and the development of voluntary agreements 
and issuance of Commission guidance. Additionally, the ECJ provides 
uniform and authoritative interpretations of EU legislation to ensure 
that they are applied in the same way in all EU member states. 
Ultimately, though, member states are given latitude in their 
enforcement practices. 

[108] Officials from the Netherlands's enforcement body told us that 
legislative changes made to national law (Aviation Act) were made in 
December 2009 to permit this body to impose repressive sanctions. 

[109] In Canada, CTA can order an airline to pay out-of-pocket 
expenses to passengers if the airline has failed to apply the 
provisions in the contract of carriage. Passengers can also submit 
claims through an alternative dispute resolution (ADR) process in the 
EU, but this option is available in only four EU member states, the 
rulings are not always binding on the airline, and ADR staff may lack 
of expertise to handle cases, especially those related to 
extraordinary circumstances. 

[110] Although DOT cannot adjudicate claims and make monetary awards, 
DOT officials noted that its enforcement staff periodically intervenes 
with airlines to obtain compensation for a passenger to which he or 
she is entitled. Additionally, according to DOT, it may obtain 
compensation for consumers through settlements of potential violations 
with airlines and may also insert such provisions into a consent order. 

[111] An even more recent report announced that the Commission will 
work with the network of national enforcement bodies to agree on 
harmonized interpretation and enforcement of the regulation. In 2011 
it will launch an Impact Assessment to assess the proportionality of 
the current measures in the light of experience and the costs of the 
regulation for stakeholders, with a view to propose further measures 
on Air Passenger Rights, including of a legislative nature, in 2012. 

[112] Passengers can use the European small claims procedure 
(Regulation (EC) 861/2007, 2007 O.J. (L 199/1)), which Commission 
officials told us aims to accelerate the settlement of small cross- 
border disputes and is available to every resident in a member state. 

[113] EU Claim is a privately funded organization headquartered in the 
Netherlands. Based on flight data it has collected, EU Claim advises 
clients about the validity of their claims against airlines pursuant 
to Regulation (EC) 261/2004 and may choose to represent these clients 
before the airline and, if necessary, court. The fee for the 
organization's services is a percentage of any compensation awarded to 
the client. 

[114] In 2009, the Netherlands collected about 750 passenger 
complaints, whereas Germany collected about 3,000. In Europe in 2009, 
a total of 35,198 complaints were received. The majority of these 
complaints (41 percent) were due to cancellations, and 25 percent were 
due to delays. 

[115] The Commission reported in 2011 that it will work with national 
enforcement bodies to promote a more uniform and quick handling of 
complaints as well as encourage airlines to establish reasonable and 
precise time frames for handling passenger claims. 

[116] We excluded commercial service, nonprimary airports because they 
handle fewer than 10,000 enplanements annually and therefore are not 
considered "hub" airports that provide connectivity to the national 
airspace system. 

[117] 14 C.F.R. part 234. 

[118] The regulation also provides for the voluntary reporting of an 
airline's entire domestic system and voluntary reporting by other 
airlines. For calendar year 2010, the reporting airlines were AirTran 
Airways, Alaska Airlines, American Airlines, American Eagle Airlines, 
Atlantic Southeast Airlines, Comair, Continental Airlines, Delta Air 
Lines, ExpressJet Airlines, Frontier Airlines, Hawaiian Airlines, 
JetBlue Airways, Mesa Airlines, Northwest Airlines, Pinnacle Airlines, 
SkyWest Airlines, Southwest Airlines, United Airlines, and US Airways. 
Other airlines reported data in other years of our analysis when they 
accounted for at least one percent of total domestic scheduled 
passenger service revenue. 

[119] Beginning in October 2008, DOT required airlines to submit 
tarmac delay statistics to ASQP for three additional categories: 
flights that are subsequently canceled or diverted or have multiple 
gate departures. For consistency, we omitted these flights from our 
analysis of tarmac delay trends from 2004 to 2010. Our analysis of 
tarmac delay trends also excluded flights reported to DOT by Atlantic 
Southeast Airlines, Hawaiian Airlines, and Comair because, according 
to DOT, these airlines inconsistently reported gate returns. 
Specifically, some airlines misreported the gate-departure or takeoff 
time resulting in an incorrect tarmac delay calculation. Further, our 
analysis excluded data for any flights with tarmac delays of more than 
10 hours since there were errors in the reporting of many such 
flights. Finally, our analysis of tarmac delay trends did not include 
data for international flights. 

[120] Additionally, our analysis excluded flights reported to DOT by 
Atlantic Southeast Airlines, Comair, and Hawaiian Airlines due to 
errors in how they reported the data to DOT. Our analysis also 
eliminated flights delayed more than 10 hours because there were 
errors in the reporting as confirmed by DOT. 

[121] Similar data was not publicly available in Canada or the EU. 

[122] While data were available for later months in 2010, which we 
could have compared with the same months in 2009, we believe that 
factors affecting cancellations during winter months differ 
considerably from factors that influence cancellations during summer 
months, when weather is less predictable ahead of time. Thus, we 
believe that if the rule has increased cancellations, it would do so 
primarily during summertime weather events, and, that is therefore, 
the focus of this model. 

[123] Both models analyze flights between 70 airports in the United 
States and Puerto Rico. The FAA Aviation System Performance Metrics 
database includes performance data on operations at 77 airports. Our 
analysis included domestic flights operated by DOT reporting airlines 
to and from these airports, with the exception of three in Alaska and 
Hawaii (Ted Stevens Anchorage International Airport, Honolulu 
International Airport, and Kahului Airport) which we chose not to 
include, and four airports (Gary Chicago International Airport, 
Greater Rockford Airport, Teterboro Airport, and Van Nuys Airport) 
that had no reported flights to or from any of the other ASPM airports 
during the months of our analysis. In addition, for the tarmac model 
(but not for the gate model) we did not include flights that were 
diverted and thus did not land at the scheduled destination airport 
and flights that had longer than a 60 minute taxi-in delay at the 
destination airport. 

[124] The number of flights included in both the tarmac and gate- 
cancellation models are somewhat less than the number of flights used 
to develop the unadjusted odds ratio because some observations that 
had missing data were deleted from the logistic model. 

[125] Each observation is one flight segment. Many passengers change 
planes and have two or more segments on a one-way trip. 

[126] Specifically, according to data on delays occurring when flights 
are under FAA control, we found that 80 percent of departure delays 
across the national airspace system were due to conditions at just 7 
of the 35 Operational Evolution Partnership airports--Newark Liberty 
International, New York LaGuardia, New York John F. Kennedy 
International, Chicago O'Hare International, Atlanta Hartsfield 
International, San Francisco International, and Philadelphia 
International. See [hyperlink, http://www.gao.gov/products/GAO-10-542]. 

[127] Data by airport was available for the 35 Operational Evolution 
Partnership airports and for the remaining airports the on-time 
performance for the entire national airspace at the relevant hours was 
used. 

[128] The airlines classified as legacy included Delta Air Lines, 
United Airlines, American Airlines, US Airways, and Continental 
Airlines. Low-cost airlines included AirTran Airways, Alaska Airlines, 
JetBlue, and Southwest. The remaining airlines were grouped as "other." 

[129] See, for example, Jing Xiong, Revealed Preference of Airlines' 
Behavior Under Air Traffic Management Initiative. 

[End of section] 

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