I know that on most of the airlines I use, you can fly with a cat in a carrier case with you in the cabin, except they only allow one per flight, so you have to get your dibs in early.I've never asked about bunnies, although I'd love to travel with Pipp.
I'm in Canada, and I make frequent trips to the States. There wasa news story I saw yesterdayabout a flying squirrel (Samantha, I think) that they're trying to deport from Canada, because of somerule against rodents. She was allowed in by mistake. I don't know if that applies tobunnies.
PS: I love that you love Pygmy rabbits. I've love to have one... or better yet, 50,000 or more. Welcome to the forum.