Is Air Travel Getting Worse? More delays, fewer accidents, and lower prices

Summary

Over the past couple of years, bad personal experiences with delays, testimonies from friends, and news or reactions to air travel incidents seem to have become much more common.It’s difficult to tell if these extra anecdotes reflect a change in the true rate of airline accidents and delays or if they instead result from fluctuations in the human social layer where confirmation bias, saliency, and mimesis can draw our concern far out of proportion.Thus, I turn to the primary source data. Here are the high-level conclusions:Long delays have become much more common. A 3-hour delay is 4x more likely in 2024 than in 1990, but airlines have masked this increase by padding scheduled flight times.Air travel remains safe; accidents are still on a slow downward trendAirfare has become much cheaper over the past 10 yearsRead on to see the primary source data from which these conclusions are drawn and for my best guesses as to what is causing these trends.The data source here is the Bureau of Transportation Statistics’ Airline On-Time Performance Data. This data covers every non-stop domestic flight in the US since 1987 and tracks scheduled and actual departure/arrival times, canceled and diverted flights, taxi-out and taxi-in times, causes of delay and cancellation, air time, and non-stop distance. All of this data is about 100gb uncompressed, so to work with the data I first aggregate up all of the numbers to the Year-Month-Route level. One way to measure delays is too look at the difference between the scheduled flight time and the actually realized flight time. If we look at the distribution of average delay across all routes in 1990, we get a graph that looks like this:The average flight on most routes arrives right around their scheduled time, some are early, some are late, with a slight skew towards delays rather than early arrivals. So if delays are getting more common and/or longer then we should see this distribution shift to the right. Here’s what it looks like in 2...