No posters of Chihuahuas sipping margaritas on the beach adorn the windows or walls at Pet Air, where clients range from cats and dogs to albino alligators. Pet Air books flights for thousands of relocating dogs, cats and exotic creatures. Do-it-yourself pet travel means long telephone waits with airlines and the stress of figuring out an unknown process, but Pet Air can take care of everything from airline reservations to a ride to the airport. In 26 years of business, not one animal has been lost in space. "We're on call 24 hours a day," says Pet Air owner John McGee, whose agency ships more than 2,000 animals a week for customers all over the United States. "All we do is specialize in live-animal shipments."