The second-busiest airport in Arizona, Tucson International Airport (TUS) is located about 8 miles south of downtown Tucson. The airport has two terminals and three runways. As a joint civil-military airport, it is also home to the Tucson Air National Guard Base. Five commercial airlines fly to and from TUS: Alaska Airlines, American Airlines, Delta Air Lines, Southwest Airlines, and United Express. In 2014, the airport handled about 3.2 million passengers. Although the airport is an international airport with customs and immigration services, there are currently no scheduled international passenger flights.