We take our 30 pound dog on AirTran all of the time. She is a foot tall and two feet in length. She can fit in coach, but we normally upgrade to business class so we're comfy and she's comfy.

They're very accommodating with pets. Just make sure to register the pet in advance with your ticket because they only allow a couple of pets per plane for saftey reasons in case of evacuation. You'll be happy to know that aircraft evacuation plans include pets as I've been told by flight attendants . . .