Flight Delays

This section provides information about airline on-time performance, flight delays, and cancellations. It is based on data filed by airlines each month with the Department of Transportation’s Bureau of Transportation Statistics (Office of Airline Information), as described in 14 CFR Part 234 of DOT's regulations. It covers nonstop scheduled-service flights between points within the United States (including territories) by the largest U.S. air carriers, including all ten carriers that have at least one percent of total domestic scheduled-service passenger revenues. These airlines account for more than 85 percent of domestic operating revenues.

The rule requires carriers to currently report on operations to and from the 29 U.S. airports that account for at least one percent of the nation's total domestic scheduled-service passenger enplanements (see Appendix for a complete list of the reportable airports).  However, all reporting airlines have voluntarily provided data for their entire domestic systems, and that information is included in this report.

A flight is counted as "on time" if it operated less than 15 minutes after the scheduled time shown in the carriers' Computerized Reservations Systems.  All tables in this report except Table 4 are based on gate arrival times; Table 4 is based on gate departure times.  Cancelled and diverted operations are counted as late.

In fulfilling DOT’s data reporting requirements, the reporting air carriers use automated and/or manual systems for collecting flight data. Those using an automated system rely on the Aircraft Communication Addressing and Reporting System (ACARS).  Based on the latest information available to DOT, of the 11 reporting air carriers, 4 (American, Northwest, United and US Airways) use ACARS exclusively; 3 (Alaska, Aloha, America West and Southwest) rely solely on their pilots, gate agents and/or ground crews to record arrival times manually; and 3 (Continental, Delta and TWA) use a combination of ACARS and manual reporting systems.

As indicated above, a carrier may voluntarily file data for its entire domestic system.  Tables 2, 3, and 4 are limited to the 29 required or "reportable" airports; Tables 5, 6 and 7 contain data on flights to/from all airports that were reported.  Tables 1 and 8 each have one column for the 29 "reportable" airports and another for all of the airports reported; see footnote C for additional explanation.

Tables 1 through 4  display percentages of flight operations that were on time, while Tables 5 and 6 show service that was late.  Tables 1, 1A, and 2 present data by carrier; airlines are ranked by performance in Table 1 and are listed in alphabetical order by carrier code in Table 2 (see Appendix for codes). Beginning with the February 1988 report, Table 1A shows carrier rankings by month and time-series data on the percentage of flight operations that arrived on time.

Tables 3 and 4 provide information by airport and time of day.  Table 5 is a list of the most frequently delayed flights, showing the percentage of each flight's operations that were late that month and the average and median number of minutes the flight was late.  The flights with the highest percentage of late operations are listed first in Table 5; where percentages are identical, flights are listed alphabetically by carrier code.  Table 6, like Tables 1, 1A, and 2, presents data by carrier, but lists the carriers in rank order from worst to best based on the number of flights which were late 70% of the time or more.  Table 7 lists more than 200 cities in alphabetical order with the corresponding on-time arrival and departure percentages.

Tables 3, 4, and 5 contain information on the time of day that a flight operated.  All times are local.  A 10:50 a.m. departure from Atlanta is 10:50 a.m. Atlanta time; if that flight arrived in Dallas at 11:45 a.m., that is 11:45 a.m. Dallas time.  If a flight's scheduled operating time changed during the month, Table 5 shows the time that was in effect for the last flight operation performed that month.

Table 8 displays the number of operations, number of flight cancellations, and percentage of cancellations by air carrier for the reportable airports and for the air carriers’ domestic system.

This report provides summary information; except for the few flights listed in Table 5, it does not show the on-time record of individual flights.  A printout showing the performance of each specific flight reported to DOT is available for inspection in the Reports Reference Room (room 4201) of the Office of Airline Information at DOT's headquarters in Washington, D.C. The on-time performance for individual markets and flights can be searched at http://www.bts.gov/ntda/oai/. Computer tapes containing data for all reported flight operations are available for purchase from the Transportation Systems Center in Cambridge, Massachusetts.  The Department cannot respond to inquiries about the performance of individual flights.

However, information on the performance of specific flights is displayed on the Computerized Reservations Systems used by most airlines and travel agencies.  Each of the reporting carriers' flights has a one-digit code between 0 and 9 representing that flight's percentage of on-time operations for the latest reported month. For example, "8" means that flight arrived on time (within 15 minutes) between 80% and 89.9% of the time during the latest reported month.