Is Your Flight Really on Time?

The majority of studies on airline delays have been based on databases that contain information only about the final delay outcome associated with a flight; that is, did a flight arrive early or late at the gate and, if so, by how many minutes? This paper uses a database from FlightStats that contains information on the timing of airline notifications of delays to customers. Specifically, the delay notification strategies of six U.S. airlines are compared, and the timing and accuracy of their delay forecasts are analyzed with data from 2010. Results show that airlines use different delay notification strategies. AirTran and Southwest announce delays more frequently throughout the flight departure process, whereas American Airlines, American Eagle, Delta, and JetBlue announce the majority of their delays in two distinct periods before departure. Results also indicate that “no news is bad news” in the sense that the closer to departure that a delay is first announced, the more likely it is to be a long delay. An assessment of forecasting accuracy reveals that the majority of airlines consistently underforecast delays; the two notable exceptions are JetBlue and AirTran. The timing and accuracy of delay forecasts has important implications for airports, particularly as it relates to their ability to develop contingency plans for irregular operations.