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Audit Reports


More Comprehensive Data Are Needed To Better Understand The Nation's Flight Delays And Their Causes

Requested By
Required by the FAA Modernization and Reform Act of 2012
Project ID
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The causes and impacts of flight delays and cancellations continue to be a key concern for Congress, the Department of Transportation, the airline industry, and the flying public. In the Federal Aviation Administration (FAA) Modernization and Reform Act of 2012, Congress directed us to examine various delay statistics, air carrier scheduling practices, and airport capacity benchmarks (i.e., the maximum number of flights an airport can safely accommodate per hour). Our audit objectives were to (1) analyze recent flight delay and cancellation trends, (2) examine air carrier scheduling practices and their relative impact in causing flight delays and cancellations, and (3) review FAA’s use of capacity benchmarks to assess airport capacity and monitor airline scheduling practices at the Nation’s largest airports.

We found that overall, flight delays fell by 33 percent from 2000 to 2012, and the number of cancellations nationwide has decreased by 56 percent at the 55 major airports. However, data limitations hinder the Department’s ability to track some of these delays or fully understand their causes. In addition, we found that air carrier scheduling practices have had a major impact on reducing the number of flight delays both nationwide and at specific airports, such as by increasing scheduled gate-to-gate times and reducing flight volume. However, over-scheduling and congestion remain a problem at several major airports, particularly in the New York area. Finally, we found that FAA’s capacity benchmarks have proven useful for assessing capacity needs at major airports; however, the Agency has not shared them with outside stakeholders and the general public since 2004.

We made five recommendations to the Office of the Secretary of Transportation (OST), FAA, and the Research and Innovative Technology Administration (RITA) to improve the collection, reporting, and communication of flight delay and other related data. The agencies concurred with three of our recommendations and partially concurred with two. Based on their responses, we consider all recommendations resolved but open pending completion of planned actions.


Closed on
No. 1 to OST
Expand the required reporting of on-time performance data to include flights by the code share partners of the reporting carriers.
Closed on
No. 2 to OST
Increase the number of carriers required to report on-time performance data by reducing the reporting threshold below 1 percent of all domestic passenger revenues.
Closed on
No. 3 to RITA
Complete ongoing efforts to identify the underlying causes of delays attributed to late arriving aircraft and make them available on BTS's public Web site.
Closed on
No. 4 to FAA
Establish and implement a policy to periodically update and publish the capacity benchmarks.
Closed on
No. 5 to FAA
Establish and implement a policy to ensure the consistent preparation, publication, and appropriate distribution of the ATO's Core 30 Monthly Delay Report.