Albuquerque International is the primary international airport serving the US State of New Mexico, the Albuquerque metropolitan area, as well as the larger Albuquerque–Santa Fe–Las Vegas CSA, handling 5,467,693 passengers in 2018. It is located in Bernalillo County, New Mexico, between the Rio Grande river and the Sandia Mountains, east of Old Town Albuquerque and Barelas, 3 miles (5 km) southeast of downtown Albuquerque. The airport serves as a focus airport for Southwest Airlines and is also served with domestic commercial flights by Advanced Air, Alaska Airlines, Allegiant Air, American Airlines, Boutique Air, Delta Airlines, Frontier Airlines, JetBlue, and United Airlines. Cargo airlines serving the airport are FedEx Express, UPS Airlines, Empire Airlines (a FedEx Feeder carrier), Ameriflight, and South Aero. The airport is designated as Class C airspace. The airport continues to share its runways with Kirtland AFB, which also handles rescue and firefighting operations. An Air Force Global Strike Command (AFGSC) installation, the host unit is the 377th Air Base Wing (377 ABW). Flying units at Kirtland AFB consist of the 58th Special Operations Wing (58 SOW) of the Air Education and Training Command (AETC) and the 150th Fighter Wing (150 FW), an Air Combat Command (ACC)-gained unit of the New Mexico Air National Guard.