In this visualization, we examine the Bureau of Transportation Statistics’ Dataset on Airline On-Time Performance (link). We take data concerning the largest 30 airports by number of flights, and then group by the same flights based on destination. The top graph to our right illustrates a curious phenomenon: As time passes, the global averages on estimated time and actual time diverge! In essence, the airlines are saying that the very same flights are getting longer, even as the flights themselves do not increase in time by the same amount. While overall air travel has gotten more hectic with greater potentials of delays, as the increasing lines both show, airlines are being progressively more generous with their allotted time, making it seem that their delays are decreasing.

Below, we offer users a way of viewing their favorite common routes and just how much, if at all, the airlines are taking liberties in building wiggle room into their scheduling. Upon clicking just one origin airport, users can see how these trends occur for all outgoing flights. If a second destination airport is selected, the data is narrowed down to the average estimated time and average actual time through the years. The data overwhelmingly illustrate the danger in immediately believing that delays are going down — even if they are nominally, that does not mean that the flights are more consistently arriving at a set time. Instead, a flight will now be estimated much more generously, giving airlines room to maneuver while still reporting “on-time” to the Bureau of Transportation Statistics.