As the Midwest continues to be crushed by the polar vortex, I found myself wondering just how operations have run this year. There have been several bad weather events that have snarled operations, so I was expecting it to be a mess. At least for the five biggest US carriers, on-time performance has been surprisingly decent, but that comes with a cost. Cancellation rates have been high. Every airline has approached operational performance differently, so let’s take a look in greater detail.
I dove into masFlight’s data for January 1 through January 28 of this year to compare the 5 biggest airlines in the US. Here’s what I found for basic on-time performance for the big 5 including regionals.

This graph make take a little getting used to, so let me break out what’s going on here. We have 5 airlines, American, Alaska, Delta, United, and Southwest. These are all reflecting their percentages, but of what exactly? From left to right:
- D0 – departures that leave exactly on time or earlier
- D5 – departures that leave no later than 5 minutes after schedule
- D15 – departures that leave no later than 15 minutes after schedule
- A0 – arrivals exactly on time or earlier
- A5 – arrivals no later than 5 minutes after schedule
- A14 – arrivals no later than 14 minutes after schedule
That last one is the DOT-published metric that you most commonly see, but there’s one more thing we need to look at to get a complete picture. Here’s the percent of completed flights by marketing carrier for the same time period.

With these two graphs, we can get a real sense of how each airline is running its operation. They’re actually quite different, so let’s dig into each one.
Alaska is Scheduling Its Flights Aggressively
If you start on the left of the top graph, you’ll see that Alaska looks good. It has rebounded from its poor Virgin America-induced performance to now being able to get airplanes off the gate in a similar fashion as the reigning champion, Delta. But when it comes to arrivals, Alaska is down toward the bottom.
This clearly shows that Alaska is scheduling tight block times, the time from when the airplane pushes back on departure to the time the seatbelt sign goes off on landing, roughly. In fact, its B0 — the percentage of flights that complete within the scheduled amount of time — is far lower than everyone else at just above 61 percent. (Next lowest is United at 68 percent.) You’ll see that has Alaska near the bottom when looking at A0, but since it gets so many airplanes off the gate on time, it ends up toward the top when it comes to A14.
While Alaska does come in second for completion factor, that number is still nothing to crow about. I think we can probably call this “the San Francisco effect.” Clouds in San Francisco makes for a rough operation for any airline. And now that Alaska is flying around there much more frequently thanks to the Virgin America acquisition, it probably has to cancel a lot more flights in order to keep the non-canceled flights running closer to on-time.
Does this tight block scheduling matter? Well, since Alaska is getting airplanes off the gate on time, that tells me it is probably building in extra ground time for aircraft turns so it can catch up when planes are late arriving. That combined with a fair number of cancellations means that Alaska can get airplanes going on time throughout the day. Arrivals may be a bit late, but that seems like a calculated risk here.
Southwest has the Opposite Problem
If you want to see the polar opposite, just look at Southwest. Its gets shockingly few airplanes off the gate on time. I mean, it’s not even close. It makes up a lot of ground in that first 15 minutes, however. Then while its arrivals tend to be far below Delta at first, by the time we get to A14, Southwest has surged into being just a hair shy of Delta.
What’s going on here? Southwest has a lot of block padding. Its B0 is the highest here at 77.4 percent. To me, this looks like a case of an airline that probably has its turn times too short, or has at least decided to trade short turn times for long block times. It can’t get off the gate fast enough, but it has enough block time padding so that by the time it arrives, it has mostly made up for it.
Meanwhile, it has canceled a lot of flights, even if that number is middle of the pack for January. I’ve generally thought of Southwest in recent years as an airline that might not get you there on time, but it’ll get you there. That January cancel rate doesn’t reflect that.
American Surprises in the Middle
American has had a really rough go of things from an operational standpoint, but in this chart, it looks like January hasn’t been too terrible for the airline. In fact, American looks pretty average in here. It gets airplanes off the gate at an ok rate and gets them back on again at a decent rate as well. Its B0 is 68.9 percent, so that’s again pretty average.
Its completion factor is not good at 97.5 percent but that too is middle of the pack. For once, American isn’t an outlier, and sadly that’s considered a positive sign. Because when American is an outlier, it’s never on the positive side of things.
United’s Long Delay and Cancellation Problem
At first glance, United and American look pretty similar. United gets about the same percentage of flights out on time as American, and with a B0 at 68 percent, it’s again similar to American. But take a look at what happens at D15 and A14. United is the one airline that can’t crack 80 percent in those two metrics.
In other words, when a United flight takes a delay, it has a better chance of taking a long delay than on any other airline. What’s even worse is United’s dismal completion rate. With more than 3.5 percent of flights canceled in January, United should be embarrassed.
This is likely a hub problem. Newark, Chicago, and San Francisco have had their issues this month. But that’s just the nature of flying in those markets. You have to plan more slack if you want to perform better.
Delta, The Champion
Speaking of planning more slack to perform better, it’s time to talk about Delta. As has long been the case, Delta is the operational champion. It gets the most airplanes off the gate on time and the most back in on time as well. And just look at that completion factor. Less than 1 percent of flights canceled when when none of the others could crack 2 percent? It’s a beautiful thing, but it doesn’t come without cost.
Delta has a fair bit of schedule padding with a B0 of 77.3 percent, just a tenth of a point behind Southwest. I’m guessing it probably has more spare aircraft as well to help avoid cancellations. But Delta has made the calculated decision that flying a solid operation can be a competitive advantage. It may be costly to run an operation like this, but Delta thinks there’s revenue benefit to be had by running better. It’s hard to argue with Delta’s numbers, though it’s not clear how much operational performance contributed to that.
From a business perspective, it’s hard for me to know what the right mix is here. But as a customer, once again Delta finds itself looking like the most attractive and reliable option. And customers should do everything they can to encourage the success of that type of operation.