Source: Source: Research and Innovative Technology Administration (RITA), U.S. Department of Transportation (US DOT).
On-Time Flight Arrivals in the United States, 1995-2011 (in %)
On-time arrivals are a commonly used performance measure in air transportation since passengers plan they trips according to the arrival schedule. In 2011 79.62% of all flights in the United States were running on time, implying that 20.38% of all flights arrived more than 15 minutes late. The main sources of delays as reported by airlines are:
  • Air carrier delay (5.15%). The cause of the cancellation or delay was due to circumstances within the airline's control (e.g. maintenance or crew problems, aircraft cleaning, baggage loading, fueling, etc.).
  • Extreme weather (0.51%). Significant meteorological conditions (actual or forecasted) that, in the judgment of the carrier, delays or prevents the operation of a flight such as a tornado, thunderstorm, blizzard or hurricane.
  • National Aviation System (5.80%). Delays and cancellations attributable to the national aviation system that refer to a broad set of conditions, such as non-extreme weather conditions, airport operations, heavy traffic volume, and air traffic control.
  • Late-arriving aircraft (6.75%). A previous flight with same aircraft arrived late, causing the present flight to depart late. This is the outcome of propagation effects on schedule integrity.
  • Security (0.04%). Delays or cancellations caused by evacuation of a terminal or concourse, re-boarding of aircraft because of security breach, inoperative screening equipment and/or long lines in excess of 29 minutes at screening areas. 
Fluctuations in the flight delay pattern are mainly attributed to the growth and decline in air traffic. If air transport grows rapidly, the outcome tends to be a decreasing performance of on-time arrivals as the system is trying to cope with additional demands with a similar level of capacity (e.g. 1995-2000 or 2003-2007). On the other hand, if air transportation stops growing or even declines, the performance improves since some flights are removed (e.g. 2000-2002 or 2007-2010).