I had a wonderful experience flying with my cat, Vern, to Aruba in January on American Airlines. I have a house here and spend months at a time on the island, so I need to have the little guy with me. As others have said, you will need a health certificate and proof of rabies vaccination from your vet. I've heard several people mention the need for an identification chip, however I haven't found any source online saying it is required. My cat doesn't have one and it was not an issue at immigration. Dogs may have different requirements. When you make your airline reservation, be sure to tell them you're flying with a pet. Your Westie will get his own record locator number for the flight - he is a passenger after all I found a really nice pet carrier here: http://www.sherpapet.com/ The site also has a section (travel > airline) to tell you the different maximum carrier dimensions for each airline.