|Number of scheduled operations||Number of delayed flights||Average minutes of delay||Percentage of delay minutes due to:|
|Carrier||Extreme weather||National aviation system||Security||Late aircraft|
NOTES: For the monthly number of carriers reporting, please refer to the Air Travel Consumer Reports available at http://airconsumer.dot.gov/reports/index.htm.
A flight is considered delayed when it arrived 15 or more minutes later than scheduled. Average minutes are calculated for delayed flights only. When multiple causes are assigned to one delayed flight, each cause is prorated based on delayed minutes for which it is responsible. Percents may not add to 100 due to rounding. Additional information is available at http://www.bts.gov/help/aviation/index.html.
SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, Office of Airline Information, TranStats Database, Airline Service Quality Performance 234, available at http://www.transtats.bts.gov/OT_Delay/OT_DelayCause1.asp as of July 2010.