On-Time Performance Has Suffered This Summer, But Some Aircraft Fared Better Than Others

American, Delta, Operations, United

Thanks to a mess of bad weather in the eastern half of the country, it has been a rough summer for airline operations. I swear it’s been so bad lately that any day I don’t receive an email with a weather waiver from one airline or another, I take notice. There’s more to it than just weather, of course, and I decided to dive into the numbers to see how things were unfolding. As usual, I went to masFlight to pull the data. In particular, I was curious to see how different aircraft types performed at the big three airlines. Sure enough, they each look very different.

To start, let’s look at the big picture. I used arrivals within 14 minutes of schedule (the DOT metric) for all of these numbers. For dates, I used June 1 through August 11 of this year. It’s no surprise that Delta did best with 80.9 percent of flights arriving within 14 minutes, but you might not know it if you were flying internationally. United was next at 75.1 percent with American just behind at 74.1 percent. These numbers all include mainline and regional carriers.

One side note: I didn’t really focus on completion factor (the percent of flights that weren’t canceled), but it’s worth nothing that there were differences here too. Delta is best at 99.1 percent with United a point behind at 98.1 percent. American brought up the rear with a pretty awful 96.6 percent rate. Most, but not all of that performance, was related to regional flight cancellations. But like I said, this post is primarily about on-time performance, so let’s stick with that. We’ll start with the worst of the bunch: American.


If you skip ahead to the other graphs, you can see that American easily has the biggest variance in performance between fleet types. There are a lot of things going on here, so I’m just going to bullet point my observations.

  • The older airplanes are at the back of the pack. The 757s that fly international, the MD-80s, the 767s, and the CRJ-200s are all on the older side and that appears to be taking its toll on American’s operation.
  • Look at that terrible MAX performance. I know Miami has had weather issues and that’s where this fleet is based, but I also wonder if there are teething issues that are slowing things down.
  • I had read in PlaneBusiness Banter that the A330-300s were having issues, and sure enough, that appears to be the case. But it’s worse than it appears here. The A330-300 has the worst completion factor of any mainline aircraft save the MD-80 at 97.4 percent. Considering those are almost all international long haul flights, that has an outsized impact.
  • The 787 fleet, as rumored, appears to have had operational issues as well. Why is the 787-9 so much better? It’s interesting, because that airplane had by far the best rate of D0, departing exactly on time (over 80 percent left as scheduled or earlier). Maybe more ground time has been scheduled to give slack on those airplanes so they don’t fall behind.
  • Hooray for the Dash-8! Of course it helps that it didn’t fly in congested airspace before it was retired, but that’s still an admirable performance for some old aircraft. Kudos to Piedmont.
  • How on earth is the domestic 757 fleet doing so well? That fleet is Phoenix-based and mostly flies to Hawai’i from there with Cancun, Washington/National, and San Diego sprinkled in. Presumably that geography helps the on-time performance.
  • NOTE: For the A321 fleet, pmAA means pre-merger American (code: 32B) while pmUS means pre-merger US Airways (code: 321).

Now, to see something that looks very different, we turn toward United.


Just look at how different United looks compared to American. United has very little variance by aircraft type which leads to a more consistent experience for travelers. But that doesn’t mean there aren’t stories to tell here.

  • Ouch, the 757-300 is having a rough summer. That airplane used to do more Hawai’i than it does currently. Now you’ll see it on a lot of hub-to-hub routes as well as in cities where there’s a lot of demand (Washington/National, Vegas, and Orlando). So it could be that the airline just overscheduled it this summer, or it could be something else.
  • If you’re flying on a Trans States Embraer 145… my condolences. That’s a poor performer as well. More than half that flying is done out of the Denver hub with the rest split between O’Hare and Dulles.
  • The sUA 757-200 stat is a bit misleading. That aircraft goes primarily between Newark and SF/LA so it’s bound to see more delays than a fleet with more variety.
  • There’s the MAX at United doing the same thing as at American — bringing up the rear. But this one is unfair since there were fewer than 400 flights for the entire time period. That being said, it also had the highest rate of cancels with 97.2 percent of flights completed. Still, it’s too early to say if this is a real ongoing issue or not.
  • NOTE: For the 757-200 fleet, sUA means pre-merger United (code: 757, the old p.s. aircraft) while sCO means pre-merger Continental (code: 752, primarily international).
  • NOTE: For the EMB-145 fleet, AX means Trans States (code: ER4) while EV/C5 means ExpressJet/Commutair (code: ERJ).

Finally, let’s turn to Delta.


As usual, Delta does better than the others, but there’s something strange here that seems counterintuitive. Usually you expect international to perform better than domestic, but that’s not what we see here.

  • The 777-200 and the A350 are doing quite poorly for Delta. These are international widebodies, so you would think they’d have a better record, but they do not. In fact, most of Deltas widebodies are bringing up the rear while the unlikely 737-800 leads. There is something going on with Delta’s international performance that should raise red flags.
  • Unlike with American, Delta’s older fleets are holding up just fine. The A320 may lag a little, but the A319, MD-88, MD-90, and even the international 767-300 fleets are performing well.
  • NOTE: The 777-200 does not include 20 flights operated by the new 777-200 that has premium economy. That is filed differently (code: 772 instead of 777). It performed poorly, but with only 20 flights I left it off.
  • NOTE: For the 757-200 fleet, “intl recliners” (code: 752) means that they use aircraft in a domestic configuration to fly internationally on routes to places like Shannon, Ponta Delgada, and Reykjavik. When they airplanes fly domestically, the code is 757. International aircraft with flat beds use the code 75W.
  • NOTE: There are 767-300s in a domestic configuration (code: 763) and in an international configuration with flat beds (code: 76W).
  • NOTE: For the EMB-175 fleet, OO is Skywest (code: E7W) while CP/YX is Compass/Republic (code: E75).

So there you have it. Everyone is having a rough summer… unless you’re flying a domestic 757 on American. There could be a million reasons why each fleet type performs as it does, but for a traveler, that doesn’t matter. All that matters (other than getting their safely, of course) is getting there on-time. Regardless of the reason, some aircraft have a better chance of that happening than others.

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23 comments on “On-Time Performance Has Suffered This Summer, But Some Aircraft Fared Better Than Others

  1. out of curiosity, why cut the data by aircraft type vs. hub or time of day or any other cross-section? 10% swing depending on a/c type is really interesting, but wonder if other key variables or insights beyond “weather in the Northeast”. For instance, is Delta’s a350 and 777’s fly more from DTW than anywhere else, was detroit hit particularly hard?

    1. noah – There are a million ways to cut it, but the original motivation for this methodology was because I had heard the American A330-300 fleet was having issues. Then I expanded the search and found it interesting. Of course any geographic isolation of fleets would have an impact, but if you’re a consumer it doesn’t matter. This is still useful to look at.

  2. Interesting that for DL the 737-900 and 757-300 did so well since they do a lot of hub-to-hub flying whereas the same plane doing the same thing over at UA did so much worse. I think it’d almost be better to slice and dice this by airport than by aircraft. Also, how do common fleet airlines compare? Did you look at WN across their various types of 737’s? What about AS with taking on the Virgin Airbuses?

  3. If the statistics by fleet type were plotted on the same scale for all carriers, characterization of what is “good” or “poor” would be different.
    Most of the US carrier widebody international operations hover pretty close to 75% with some exceptions above and below that line. Also, international operations are not included in US DOT numbers, in part because 15 minutes on a 12 hour international flight are not terribly significant while 15 minutes as a percentage of a 2 hour domestic flight is significant. Further, customer perception of on-time for an international flight is much more closely tied to international customs clearance which also includes baggage claim. Customs clearance can vary significantly by country – and may not even apply if making an international to international connection in another country. And most importantly, foreign carriers do not have equal on-time requirements as US carriers. US carriers operating in some parts of the world do have costly customer service penalties to pay if flights are late which are based on different sets of standards. For multiple reasons, international flights are not included in DOT statistics and comparing them to domestic flights doesn’t make much sense.

    Finally, focusing just on a few fleet types for the US3 omits a number of other US carriers that operate far more domestic flights on a single fleet type which is all or the majority of all the flights they operate. Several low cost carriers have worse domestic on-time performance for far more flights on a single fleet type than any US3 carrier.

  4. I didn’t even realize anyone was still flying the MD-80. Then again, Delta lists the MD-88 and MD-90, and the 717? Are they buying used plane lots or just buying them out?

    Sad to see the data on Delta’s A350, and too bad we don’t have more data comparison points on that one, since they’re the only US carrier flying it. I have high hopes for that plane, it seems like the the “baby bear” plane in a lot of ways (just right in other words).

    1. Others can speak to it in greater detail, but my understanding is that Delta has been pretty successful at buying older aircraft types at prices low enough to more than make up for the higher costs (fuel + maintenance) that older planes typically carry.

      Personally, I’m a fan of the Mad Dogs (MD-8x and MD-9x series), as well as the Boeing 717. Especially with today’s basic economy fare that often do not include seat assignments, I like the 3-2 seating configuration and the fact that < 20% of the seats on the plane (when one includes emergency exit rows) are middle seats.

  5. It’s possible parts of Delta’s issues are a) ATC delays in China, which is where a lot of 777 and A350 routes go to, and b) holding international flights departing the hub to wait for late inbound connections. But agree it’s unusual to see that kind of pattern.

    I’ve heard anecdotal stories about A350 delays due to maintenance which are presumably teething issues more than anything, but that shouldn’t affect the 777. Perhaps having some 777s out of service for cabin overhauls has also taken some needed slack out of that fleet.

  6. The irony with AA is that weather has been pretty much nonexistent at DFW all summer until the last week or so. You’d think that would result in better numbers.

  7. I’m interested in how Southwest fairs with its Max 8 fleet & with International? (They are a Top 3 US carrier after all!)

  8. Whoops, somehow the text didn’t come through…

    Fascinating analysis as usual. Is there a place that lists all aircraft codes by the airline with the deciphering you provided above? Seat guru has some of it, but I find it often incorrect/outdated.

    1. Dima – I don’t think there is since airlines sometimes use codes differently than as intended. But if you have specific questions, I can provide.

  9. A sad commentary on Frontier Airlines. My daughter and her two children(9&7) visited us in Boise Id and had their return flight of 8/13/18 cancelled. This was the only flight for the day to Denver Co. She was informed that they were re-booked on a return flight on Frontier for 8/16 or would receive a $400.00 refund. No other options! We finally Got them flights on Southwest on 8/14. at the cost of approx.1100.00. Frontier offered a reimbursement of their fare(500.00), Take it or leave it.

    1. Lesson learned. Spirit,Frontier,Allegiant,SunCountry all Ultra-low cost carriers = You get what you pay for.

      1. I agree. As an aside, given the size of many American waistlines (mine especially), I’d argue that Spirit’s 28″ pitch should be considered cruel and unusual (masochistic) punishment for anyone with a BMI over 30, and that it should come with a referral to a local chiropractor.

        That said, I’m happy that small price differences are enough to get other pax to choose ULCCs over legacy airlines, as that helps force the legacy carriers to keep their basic economy fares reasonably competitive for the rest of us.

        1. I’m not a fan of tight seats either, but the waistlines part is a bit specious – pitch refers to the distance between the seat rows, not the width of the seat itself.

          1. Good point. As a person of size (though thankfully not quite large enough to need a seatbelt extender), I really should be caring about the distance between the armrests first, and the seat pitch second.

            I did a Meridiana (now Air Italy) roundtrip a year ago from JFK to NAP, and while it was worth it for the savings and the convenience of a nonstop, the 767 I was in had one seat more per row than normal, and sitting in a seat with an inch or two less hip room than normal (never mind my gut, just from hip to hip) was very noticeable. That said, I’d do it again to save a stop in Europe and $400-500 RT.

  10. I don’t know why Delta doesn’t just update their block time on their DTW-PVG flight. We flew that flight and took a delay due to the boarding process. I watched that flight for a while prior to our trip, there was very little slack in the system, if everything ran on-time they had around 2 hours to turn it from an inbound NRT flight, if that flight’s late at all, they’d be late. Sometimes, they just didn’t have a plane so they’d use the PEK inbound which arrives after the DTW-PVG scheduled departure time, taking in a delay. They did have a couple of mechanical issues, but I think most of the lateness may be attributed to that particular flight due to scheduling….

  11. Some have asked about Southwest. I didn’t include because there’s basically no variation between fleets:
    737-800 – 76.9%
    737-700 – 74.9%
    737 MAX 8 – 76.2%

    1. Very interesting that their MAX 8’s have essentially the same reliability as the other types. I wonder why AA is having teething issues? Oh wait, dumb question- AA is a mess.

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