How big is the "underseat area"?

I just wrote a blog post on this subject.

Airlines don't normally publish underseat sizes. However, to get an idea, find the maximum allowed pet carrier the airline will allow passengers to bring on board. They must be placed under the seat in front of you so whatever size is given means a bag of that size or smaller "should" fit.

Then go to seatguru.com, find your plane and look at the seat chart. Make sure there is nothing under the seat in front of you.

It will also depend on if you have the aisle, middle or window seat. Usually the middle seat has the largest area and the aisle has the least.

What I'm going to say will only be an issue if you're trying to utilize every single cubic inch of space under the seat in front AND you're on an over the water aircraft that is fitted with the 110 volt under-the-seat electrical outlet. The box housing this electrical outlet must hang down (I didn't measure it, but....) about 2 inches. I was recently on a Boeing 777-Extended Range aircraft where they provide the electrical outlet, very convenient, but if someone were trying to utilize every cubic inch of space under the seat in front of them, it gets in the way a bit.

Interesting idea, Frank! Of course Delta doesn't publish information on kennel sizes either. Will need to give them a call I guess. I looked at your blog briefly and will spend some more time there when I get a chance.

Frank II's and Kent's point about different space under different seats is important. If you get the seat with the entertainment system box for your row, or have an electrical outlet, or you're on the aisle (so there's a "bar" dividing the underseat area from the aisle), you will have less space (sometimes significantly less) than a seat without these "features."

As the others mentioned, some seats have electronics mounted underneath which will restrict room for baggage (or your feet). Seat Guru usually lists which seats have those, so be sure to choose your seats carefully. Also, don't pick the front row as there's no under seat storage and the seats are narrower, as they have to allow room for the TV monitor in the arm rest.

Spirit Airline charges for any carry-on that will be put in the overhead bin. They do allow a free carry-on if it is less than 16" x 14" x 12", but they say it has to go under the seat, so I imagine the under- seat area will fit that size - probably on any airline. If your 17" x 15" tote bag is not stuffed, I would think it would fit. OTOH, United limits the size of a personal item to 17" x 10" x 9" and has sizers (yet to be used) at the gate, so if Delta does the same, it won't pass.