We just returned from a trip to the Bay Area via Virgin America, so I had two chances to check out Virgin’s A320 under-seat measurements. Unlike JetBlue, which also flies A320 planes, Virgin America divides its A320s into two classes (First and Main). First Class has two seats on each side of the aisle, while the main cabin has three seats on each side of the aisle.

There is a bulkhead between the two classes, and you are not allowed to sit there with a dog. There is also a bulkhead in front of the first First Class row, and the same goes there.

The only First Class row that has under-seat space, in fact, is Row 2. However, although I couldn’t get close enough to get you exact measurements, I can assure you that the only dog that would fit under a First Class seat is a teacup-sized dog in a purse-style carrier lying on its side. If you have an in-cabin dog, the main cabin is the only way to go. [4/22/10 My husband just traveled First Class on a Virgin America A320, and confirms that there is no under-seat space in First Class. All your carry-on items have to go in the overhead compartment.]

Your best choice is an aisle or middle seat. All three seats carry a life vest packet enclosed in a firm plastic container, so the under-seat height is a fixed 8.5 inches. The aisle seat space is 18″ wide (that is, measured left to right), and so is the middle seat space, even though there is a box for electronics on one side. The window seat space is slightly narrower, at 17″ wide.

Although my carrier was 10.5″ tall, it flexed just enough to squeak under the seat. This is another place, however, where I would have liked to have been using our SturdiProducts carrier, which flexes more easily.

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).