Its just like with any animal preperations when PCSing, you will have to check out the local laws and plan accordingly. I had a friend PCS to RAF Lakenheath in England with her BRB. She did all the paperwork and had the animal cleared by a VET. However, Heathrow Airport's animal control took the BRB and she never saw it again. So my advice is, try to contact the airport animal control (for the specific airport you would be flying into) and find out from them what you should do.