I flew on two separate Continental 737s last week, both -800/900 series planes, and there were dramatic differences in their under-seat spaces. On both flights, I was in Economy class. I had purchased seats with extra leg room (which I always recommend when you’re traveling with an in-cabin dog, though I know it’s not always financially feasible), but the under-seat spaces for those seats are not any different from the regular Economy seats.

On my first flight, from Seattle to Houston, I honestly don’t know how I could have fit Chloe under any of the seats. The best choice was the middle seat, which had an under-seat space 16″ wide. The window seat space was 14″ wide, and the aisle seat space was 13″ wide. All three spaces were about 17″ deep (measured from the bar behind the heels of the person in front of me to about two inches out from the plane of the seat pocket in front of me). The under-seat space height was also grim: It started at 10.25″ tall, then quickly (within about 4 inches) lowered to 8.5 inches. Between the hard lifejacket cases at the top of the under-seat spaces, and the two big electronics boxes along the sides of the window and middle seat spaces, there just wasn’t a heck of a lot of room available.

On the second flight, from Houston to Tampa, things were strangely different (on the same model of plane!). The lifejacket boxes were oriented perpendicularly to the floor, and rested against the very back of the under-seat space (right behind the heels of the people in front of you), so the height of the under-seat space was a uniform (and lofty!) 11 inches but the depth was very shallow — only 14 inches. The middle seat was again the best choice: On this flight, the middle seat space was 16.5″ wide, the window seat space was 15″ wide, and the aisle space was 12.5″ wide.

On both planes, the First Class under-seat spaces looked similar, but I couldn’t get close enough to get any measurements for you.

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).