King County International Airport, commonly known as Boeing Field, is a public airport owned and operated by King County, 5 mi (8.0 km) south of downtown Seattle, in the U.S. state of Washington. The airport is sometimes referred to as KCIA, but it is not the airport identifier. The airport has scheduled passenger service operated by Kenmore Air, a commuter air carrier, and was being served by JSX with regional jet flights. It is also a hub for UPS Airlines. It is also used by other cargo airlines and general aviation aircraft. The airfield is named for founder of Boeing, William E. Boeing, and was constructed in 1928, serving as the city's primary airport until the opening of Seattle–Tacoma International Airport in 1944. The airport's property is mostly in Seattle just south of Georgetown, with its southern tip extending into Tukwila. The airport covers 634 acres (257 ha), averages more than 180,000 operations annually, and has approximately 380 based aircraft.