Phoenix Sky Harbor International Airport (IATA: PHX, ICAO: KPHX, FAA LID: PHX) is a civil-military public international airport 3 miles (2.6 nmi; 4.8 km) east of downtown Phoenix, in Maricopa County, Arizona, United States. It is Arizona's largest and busiest airport. Among the largest commercial airports in the United States, PHX was the 11th-busiest airport in the United States in terms of passenger boardings and 38th-busiest in the world in 2025. The airport serves as a hub for American Airlines and a base for Frontier Airlines and Southwest Airlines. The airport is also home to the 161st Air Refueling Wing (161 ARW), an Air Mobility Command (AMC)–gained unit of the Arizona Air National Guard. The military enclave is known as Goldwater Air National Guard Base. One of two flying units in the Arizona ANG, the 161 ARW flies the KC-135R Stratotanker aircraft.