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Flying with an in-cabin pet: Under-seat measurements for Southwest 737-800 planes

Returning to Seattle from a week in North Carolina (which explains why things have been so quiet on the blog recently), I flew for the first time on one of Southwest’s new 737-800 planes — so new, in fact, that it smelled like new plane, which is just as pleasing as new car. You’ll like them, when you get on one — the top half of the bulkhead between the first row and the flight attendants is gone, and in general the plane feels wider and more open; the overhead baggage compartments hold more stuff and are easier to close; and the flight attendant call button is located far, far away from the reading light buttons.

Anyway, it’s a new plane to me, so I grabbed my tape measure and threw myself on the ground. Here’s what I learned. As on other Southwest planes, the depth of the under-seat space (measured from the rail just behind the heels of the person in front of you to the nearest end of the bracket supporting the seat in front of you) is 17″. There are packets under each seat holding a life jacket, but they are soft, and can be pressed upwards — the under-seat height, therefore, is 11.5″ to 12″. The aisle seats have one of those pesky bars running around the under-seat space, reducing the available width to 14.25″, but the middle seat space is a generous 20″ wide, and the window seat space is a very respectable 18.5″ wide.

If you compare these measurements to Southwest’s 737-700 measurements, you’ll see that the middle and window under-seat spaces on the -800 series have more left-to-right room, and the change from a hard to soft enclosure for the life jackets means that all of the under-seat spaces are effectively 2-3″ taller. If you walk on a Southwest plane and can see the first port-side row from the door, start smiling — you’re on a 737-800, and your pet’s carrier will fit way more easily under your seat than you’re used to.

This post is part of an ongoing series recording under-seat measurements of the various planes we fly on. Keep in mind that most domestic and international airlines have rules about the maximum size of in-cabin pet carriers they allow on board (see Dog Jaunt’s handy charts under the “Taking your pet on a plane” tab above).


  • Heather

    I love the blog!! I will be flying with my 10 pound Maltipoo for the first time in April, and this blog has given me all the information I could ever need! I was a little unsure about the pet carrier height requirements of the Southwest flights until I stumbled across your blog. However, I was wondering if you have heard anything about the Sherpa Hybrid Eva Carrier? Or if maybe anyone else has flown with the carrier before on Southwest flights? (I know I am probably narrowing the pool by a lot there.) It seems as though the dimensions are not listed correctly, and the height when measured at the tallest point is more like 10″ to 10.5″, instead of 12″. This made me wonder about the dimensions listed for carriers, like the large SturdiBag that you use on Southwest flights. Are they accurate?

    I am also curious about calming remedies, specifically Happy Traveler. (Recommended by a friend.) He is not a very anxious dog usually but I don’t know how he will do with a mass amount of people in one place, especially in the security line. I want to give him something to keep him calm but not knock him out. Have you ever used or heard of this?


  • Ding-dangit, Heather, I took too long to respond to this. I sincerely hope your April flight went okay! I’m uneasy about the carrier you pointed me to, since its sides are hard, and won’t let the carrier compress readily around under-seat obstructions. The top is soft, so you might be able to angle it around prominences, but I think you’d be better advised to buy the large SturdiBag that’s worked so well for me and Chloe. I have used Happy Traveler, and it might have helped Chloe a bit (she doesn’t like takeoff and landings). I suspect that keeping your hand in with him might be enough to keep him calm, especially if he’s normally a calm guy. Of course, this is all ancient history by now. How did it go?

  • Shaun

    We have two Frenchies that we’re considering to fly with us from the Southeast US to the West Coast layover in Chicago. They both weigh 25 lbs and probably is taller than the seat height you referenced. Laying down they’ll be okay. Any tips other than what you’ve already mentioned? Thank you. -Shaun

  • Hi, Shaun — Are you planning to have them in the same carrier, or two different carriers? And it looks like you’re planning on flying Southwest, right?

  • Shaun

    Hi Mary-Alice. We will be flying them on SWA in separate carriers. So my guess is a window and a middle seat will be the best bet. I’m more concerned with whether they’ll get through security and the SWA ticketing counter. We experienced a difficult time on Delta with first class tickets. So it probably doesn’t matter as much to the class of seats more on the under seat capacity. That is why I’m looking at SWA which appears to have more height room.

  • Ack! I lost track of your reply for a day there…. We traveled back from Ohio at Christmas with two pets — Chloe and our new cat Cora — and did just fine on Southwest. You’re right, this is no time for First Class. The under-seat space on Southwest is generous, and we didn’t experience any issues at all at the ticketing counter or at any time on the journey. Here’s the link to my post about the trip: Safe travels, and please let us know how it goes!

  • Shaun

    Mary-Alice, I apologize for the late response. We just returned back from our trip. We decided against taking the Frenchies with us and were happy we made the right decision. The space under the seats would have been too low. In addition we had connecting flights with short layover times. We’ll do a road trip instead. Thanks again for your input and the posts on your website. -Shaun

  • Tara

    First of all, thank your this information. It was very helpful. I travel every week for work but never travel with my cat. I travelled on 10/31, LAS to PHL on SW. We were very lucky to be on the 800. The entire process from check in to boarding was very nice. I took my 12 lb cat in the Medium Sherpa. I did buy and bring the small Sherpa with me in case anyone told me that I could not get on the plane with the medium. No one even looked twice (can you say RETURN? :-)). The Medium Sherpa fit under the middle seat perfectly. No jamming, no squishing…nothing. It was perfect. I am so happy I did not have to place my cat in the small, she looked like a sausage in it. Thank you again for this information!

  • Bobbie

    Love your site! I’m about to fly out of Hawaii to Alabama and I’m taking three different airplanes a Delta 737-900ER, 767, and a MD88? I think lol I’m going today to see if I can find a Sturdibag (large) for my Mini Schnauzer that weights 17lbs. The only flight that I have that concerns me it the first one cause they told me it is only 9in high! That seems so small but I’ve measured my pup every way possible and he will fit the space no problem. I’m just worried about if they allow for the top to squish down on the carrier. Wish me luck!

  • Thank you, Bobbie! Luck to you and the pup, of course — if it’s any comfort, I’d do it with Chloe, and I would absolutely choose the large SturdiBag. It’s the best bag I know of for fitting into those odd spots. If challenged, project an air of calm confidence (but not, of course, sassiness), assure them you do this all this time and you know your pup will fit comfortably — and please send pictures and info about your flights, if you would, to give future travelers the info they’ll need to project that air of confidence….

  • Donna

    Hi, I have a question about a carrier I purchased. I have a 8 week old german shepard puppy, who weighs roughly 10 pounds. I will be traveling with tomorrow on southwest. I have a Petmate soft sided kennel cab, measurements 20 x11.5 x 12. I am nervous about this fitting under the seat. There have been so many conflicting stories on the height, so, I can be more re assured that it will fit. My puppy fits fine and can move around in it. (we been practicing). Could you please let me know what you think?

  • Hi, Donna — I think you guys will be just fine. An 11.5″ tall soft-sided carrier will flex downwards a bit around the bits it needs to accommodate (like life vest containers), and your pup is small enough (ha! that won’t last long!) that there’s room above him/her for the carrier to flex down into. As always, my advice is to take courage from that, and when you arrive at the airport, do not ask for advice and do not express your anxieties to an airline rep. Project an air of calm confidence, as if you guys had just been jaunting around the U.S. on three other Southwest flights. Make cooing noises at your pup and tell the world what a good little traveler s/he is. You can totally do this!

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