Salt Lake City International Airport is the only airport with scheduled passenger service in the county, and South Valley Regional Airport is the only other public airport. Another small airport, Skypark Airport, is just to the north of Salt Lake County. Salt Lake City International Airport is the 24th-busiest airport in the United States and a hub of Delta Air Lines and SkyWest Airlines. In 2014, construction began on a major renovation and expansion project that is expected to be completed in 2022.