DELAYED GRATIFICATION

A deep dive into U.S. flight delays

a CS 1710 final project by

Dylan Park, Paurakh Rijal, and Pranay Varada

Every year, millions of travelers face unexpected flight delays, disrupting plans and causing significant frustration. But where are these delays happening, and why? We looked at arrival delay data from the Bureau of Transportation Statistics to find out.

Scroll through this interactive story to discover which airports and carriers are most affected by delays, and how likely you might be to experience a delay on your next flight.

To begin, here’s a map of every major airport in the United States. Hover over an airport to see its number of flights and average arrival delay.

*Note that all of the delays in this story refer specifically to arrival delays: the difference between the time a flight arrives at an airport and when it was scheduled to arrive.

(De)lay of the land: where U.S. airport delays occur

Airports sized by average arrival delay

Most delayed airports and busiest airports highlighted

The U.S.’s most delayed airports are in some unexpected places: Provo, Utah; Santa Maria, California; and Joplin, Missouri, among others. All three of those airports see average delays of over 25 minutes. Of the country’s busiest airports, Orlando International and New York’s John F. Kennedy International are among the most delayed, with average arrival delays of nearly 20 minutes. Meanwhile, the world's busiest airport, Hartsfield-Jackson Atlanta International, does a pretty good job of managing delays – just 12.5 minutes on average.

But how much of these delays are the airport’s fault, and how much is the fault of the airline? Find out how different carriers perform in the graph below.

Why your flight is late

How America's top airlines compare in the reasons for their delays

Reason for delay

Carrier

Late aircraft

National Airspace System (NAS)*

Weather

*Non-extreme weather, airport operations, air traffic control, etc.

The plot above details carriers’ arrival delay performance, segmented by cause:

  • Carrier delay (a delay under the carrier’s control, such as maintenance or loading baggage);
  • Late aircraft delay (caused by the plane’s late arrival at a previous airport);
  • NAS delay (caused by the FAA’s National Airspace System);
  • and weather (generally extreme conditions).

JetBlue leads – or trails – major carriers in the U.S. in terms of all delays, with delayed JetBlue flights experiencing an average of over 25 minutes in holdups. Low-cost airlines are particularly notorious for their delays: the second- and third-most delayed airlines are Frontier and Spirit, and Spirit has the most late aircraft delays of any airline. (Note that JetBlue can also be classified as a low-cost carrier in many respects.)

The country’s three biggest airlines – American, United, and Delta – are middling in terms of their delay performance. Alaska Airlines is the U.S.’s least-delayed airline, with an impressive average delay of just 9.6 minutes.

This highlights an astounding fact: JetBlue’s average carrier delay of 10.5 minutes is longer than the entirety of the average Alaska Airlines holdup. Below, take a closer look at how JetBlue’s delayed flights compare to those of other airlines.

JetBlue: America's most delayed airline

Comparisons to all other airlines

Average delay (minutes)

Delayed flights with 15+ min delays (percentage)

Carrier delay (minutes)

Late aircraft delay (minutes)

So if you’re flying JetBlue anytime soon, you might want to be a little bit wary of possible delays!

Speaking of upcoming flights, though – should you expect longer delays during the holiday season, no matter what airline you’re flying? This next graph shows the breakdown of arrival delays during each month in 2023.

How delays change by the months

Winter might actually be the best time to fly

Carrier

Late aircraft

NAS

Weather

Surprisingly, delays are actually at their lowest in November and December! It turns out that despite the perception of the busy holiday season, there are more flights and more people flying in the summer months, especially in June or July, which can contribute to delays. Extreme weather also isn’t a huge factor – it’s how airports and airlines react to it. Summer weather events, whether heat waves or hurricanes, can pose just as big a problem as snow, if not bigger, for flight delays.

Below, check out how flight volume could be affecting delay times.

Does flight traffic affect delays?

The answer: potentially!

Total flights

Average Delay (min)

July and August see the most flights, with around 640,000 per month. That’s about 7% higher than November and December. January and February, meanwhile, see the fewest flights. Interestingly, despite the fact that there’s only a slight decline in the number of flights towards the end of the year, delays drop way down – they basically halve from summer to late fall. Perhaps with airports running at full capacity, a 7% drop in flights can make all the difference in the world.

Now, it’s your turn! In the interactive visualization below, select any combination of airport and airline, and find out how long the average arrival delay is at your next destination.

How long can you expect to be delayed?

See how the average delay of your chosen airport and airline compares to the overall distribution of delays

Hopefully, you’re coming out of this article with the tools to avoid getting delayed on your next flight. It doesn’t necessarily matter how big the airport you’re flying into is: delays can come about because of the weather at your destination, how airports and airlines deal with those complexities, and which airline that airport is a hub for. You might want to avoid flying into smaller, regional airports where weather or staffing could be an issue, or on low-cost airlines like JetBlue that seem to be more responsible for delays. Of course, there are always exceptions – Southwest flights don’t get delayed very long on average. But these are just a few things to take into consideration when planning your next trip.

Just don’t fly JetBlue to Provo. (You can’t actually do that, but it’s worth mentioning regardless.)

Thanks for reading!