Source: Research and Innovative Technology Administration (RITA), U.S. Department of Transportation (US DOT).
On-time arrivals are a commonly used performance measure in air transportation since passengers plan their trips according to the arrival schedule, including connecting flights. 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 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 the same aircraft arrived late, causing the present flight to depart late. This is the outcome of propagation effects on schedule integrity since a plane is usually scheduled for several flights during the day.
- Security (0.04%). Delays or cancellations caused by evacuation of a terminal or concourse, re-boarding of aircraft because of a security breach, inoperative screening equipment, and long lines in excess of 29 minutes at screening areas.
Fluctuations in the flight delay pattern are mainly attributed to the growth and decline rates of 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, 2003-2007, or 2012-2014). On the other hand, if air traffic stops growing or even declines, the performance improves since some flights are removed (e.g. 2000-2002 or 2007-2010). The substantial drop in air traffic during the Covid-19 pandemic in 2020 was associated with an increase in performance.