An estimated 2 million animals travel on airplanes each year. In the late '80s they could fly as excess baggage for $30 to $35, depending on the airline. Today, Garfield, Fido and friends will cost you $100 to $125 if they're shipped as carry-on luggage, or up to $250 in a checked kennel. One saving grace: on Continental, your furry companion can earn you frequent-flyer mileage.