Source: Source: Research and Innovative Technology Administration (RITA), U.S. Department of Transportation (US DOT).
- 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.