NOTES: Air Carrier Delay-the cause of the cancellation or delay was due to circumstances within the airline’s control (e.g. maintenance or crew problems, etc.). Extreme Weather Delays-significant meteorological conditions (actual or forecasted) that, in the judgment of the carrier, delays or prevents the operation of a flight. National Aviation System Delay-delays and cancellations attributable to the national aviation system refer to a broad set of conditions non-extreme weather conditions, airport operations, heavy traffic volume, air traffic control, etc. Security Delay-delays caused by evacuation of terminal or concourse, reboarding of aircraft because of security breech, inoperative screening equipment and long lines in excess of 29 minutes at screening areas. Late Arriving Aircraft Delay-previous flight with same aircraft arrived late which caused the present flight to depart late.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, Transtats Database, Airline On-Time Performance, available at http://www.transtats.bts.gov/ as of May 2016.