Who knew that there were still DC-9s out there? It turns out that Delta has quite a few of these planes of my youth, though they’re likely to be retired in favor of more fuel-efficient alternatives. That’ll be a shame for Chloe, because the under-seat space on a Delta DC-9 has to be seen to be believed.

First Class has two seats on each side of the aisle, and Economy Class has two seats on one side and three seats on the other side of the aisle. As always, I only saw the First Class spaces in passing (but they looked promising, and this is not a plane that will be burdened with electronics boxes, even in First Class).

Your best choice on these planes is an aisle or middle seat. The height of the space is a generous 11.5 inches, and the depth (measured front to back) is a standard 17 inches. The aisle seat space is 20.5 inches wide, the middle seat space is an astonishing 21.25 inches wide, and the window seat space is a nearly-unusable 11.5 inches wide.

Please note that we sat on the three-seat side of Economy Class, so I don’t have measurements for the two-seat side. I suspect that the aisle seat space is substantial and the window seat space is cramped, but that’s a guess.

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).