Delta’s A319 planes are divided into two classes, First and Economy. We were traveling in Economy, which has three seats on each side of the aisle. Row 9 is an exit row, so you will not be able to sit there with your dog. Row 5 has a bulkhead in front of it, but even though the bulkhead has large cut-outs that let you stick your purse, etc. under the last row of First Class, you cannot have an in-cabin dog in that row. [I just spent — and I am not exaggerating — an hour on the phone with Delta finding out about Row 5. I was disconnected four times. Argh!!]
In this plane, your best choice is a middle seat. The under-seat space is 11.5 inches tall, and about 17 inches deep (that is, measured from front to back). Measuring from left to right, the middle seat space is 19.5 inches wide. The window seat space is 17 inches wide and the aisle seat space is 17.5 inches wide.
First Class has two seats on each side of the aisle, and although I didn’t have the chance to throw myself under a seat and measure the available spaces, it looked like there might be sufficient space for an in-cabin dog under the window and middle under-seat areas (there are three, even though there are only two seats above them). The space next to the aisle is too narrow for a pet carrier.
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).