Spokesman Perry Cooper says the early damage estimate from the blaze is $250,000.
He said airport firefighters responded about 7 a.m. Tuesday to a report of multiple cars on fire on the sixth floor of the garage. The blaze sent clouds of smoke wafting through the area.
Firefighters from nearby departments responded, and the blaze was brought under control.
Cooper says investigators believe the fire was started by a mechanical failure in one of the vehicles.
Cooper says airport operations remained normal. The arrival and departure drives remained open. Ticketing and flights were not affected, and no one was injured.
Smoke closed a service tunnel at the airport. Doors to the north end of the terminal were closed when smoke started to drift in.
Cooper says the airport is trying to identify owners through license plate numbers to let them know what they'll find when they return home.