About 78 percent of domestic air carrier scheduled flights arrived on time in 2004, compared with 79 percent in 1995. The number of on-time flights peaked in 2002 and 2003 (82 percent), after a low of 73 percent in 2000. The number of canceled and diverted flights declined to their lowest level in 2002 (less than 2 percent) (figure 5-6).
The total number of scheduled domestic passenger flights at the nation's airports rose 12 percent between 1995 and 2001 from 5.3 million to 5.9 million flights. After the shutdown of flight operations on September 11, 2001, the number of scheduled flights decreased 12 percent between 2001 and 2002 to 5.3 million flights. They then rose 23 percent to 6.5 million flights in 2003 and 10 percent to 7.1 millions flights the following year.
Air carriers with at least1 percent of total domestic scheduled service passenger revenues have been required to report on-time performance data since 1987. As of mid-2003, the airlines began reporting data on the cause of delays as well.1 A flight has an on-time departure if the aircraft leaves the airport gate less than 15 minutes after its scheduled departure time, regardless of the time the aircraft actually lifts off from the runway. An arriving flight is counted as on time if it arrives less than 15 minutes after its scheduled gate arrival time.
On average in 2004, National Airspace System delays2 had the most impact on airline schedules, accounting for almost 40 percent of all delays (figure 5-7). Another 26 percent of delays occurred, on average, because of circumstances within an airline's control (e.g., maintenance or crew problems), while 30 percent were caused by a previous flight arriving late. At 5.0 percent and 0.3 percent, respectively, extreme weather and airport security caused the fewest delays, on average, in 2004. The number of weather-related delays, however, varied by month and was highest in June 2004 (9,339 delayed flights) and lowest in April 2004 (3,129 delayed flights). By month in 2004, total delays ranged from 15 percent to 36 percent of all scheduled flights.
1. U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, Airline Service Quality Performance data, March 2005.
1 See table 5-7 in appendix B for details on reporting carriers and detailed information on cause-of-delay categories.
2 The reasons for National Airspace System delays include nonextreme weather conditions, airport operations, heavy traffic volume, and air traffic control.