Top Airlines and Airports for Delays: Part 1

Inspired by a particularly nightmarish travel week, I've started digging into publicly available airline on-time data from the Bureau of Transportation Statistics (BTS). I wanted to know, what airlines are the worst offenders? Which major airports are the most likely to be hit with delays? 

Here's a first pass at digging into the data. These are percentages of arriving flights delayed by fifteen minutes or more, at major airports. 

Among airlines, in the first two quarters of 2014, Southwest, Frontier, JetBlue, ExpressJet, and American Eagle were the most frequently delayed by fifteen minutes or more. There is also a good deal of month-to-month variation in delay rates. (Graphic made using Tableau, with BTS data.)

Worst airport offenders were San Francisco, Chicago O'Hare, and Newark. (Graphic made with Tableau using BTS data.)

According to the BTS (the graphic below is theirs), the largest single source of delays is the aircraft arriving late, followed by National Aviation System delays. 

Next time we look at this, I'll dig into which departing airport/ destination airport combinations are most likely to come with delays.