The number of flights not arriving on time is a measures of service quality. This indicator is strongly seasonal and is affected by weather and heavy demand in winter and summer months, respectively. The data cover the 10 largest U.S. air carriers. A scheduled operation consists of any nonstop segment of a flight. The term "late" is defined as 15 minutes after the scheduled arrival time.
|Flights not arriving on time (percent)||22.50||22.36|
|Percent change from same month previous year||-4.09||-0.62|
NOTES: The current value is compared to the value from the same period in the previous year to account for seasonality. Data for American Eagle was included starting in January 2000. Percent changes from January 1999 to January 2000 were calculated based on data excluding American Eagle. Aloha Airlines, which reported on-time statistics for October 2000 through November 2001, has been excluded to retain comparability. Hawaiian Airlines started voluntary reporting the data in November 2003, also has been excluded.
Certain flights originating at O'Hare airport and operated by American Airlines (181 flights in April) and United Airlines (256 flights in April) between April 24, 2002 and May 8, 2002 are not included in the calculations due to the participation of these carriers in a pilot test program for enhanced baggage screening. A list of affected flights affected is available from BTS.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, Airline Service Quality Performance data, April 2005.