Des Moines International Airport is a commercial service airport 5 miles (8 km) southwest of Des Moines, the capital of Iowa. The airport's 2,600 acre campus includes two runways, 46 buildings, 7 parking facilities, and the terminal. Six commercial airlines offer service from DSM (American, Allegiant, Delta, Frontier, Southwest and United). The airport is managed by the Des Moines Airport Authority. The National Plan of Integrated Airport Systems for 2017–2021 called it a primary commercial service airport. In 2016 a record 2.48 million passengers used the airport, up 5 percent from 2015. In 2019, DSM served 2.92 million passengers, a record for the airport. The airport hosts the 132nd Wing of the Iowa Air National Guard. In the 1920s the Des Moines area had several small airports for general aviation and airmail. In 1929, the Iowa General Assembly passed a law allowing cities to sell bonds and levy assessments to build municipal airports. Over 80 sites were considered for the Des Moines Airport until a decision was made to build on 160 acres (0.65 km2) of farmland south of the city. Construction of the airport began in 1932 and was completed in 1933. The airport's first passenger terminal was built shortly after the airport was completed. It was replaced by a new terminal in 1950 that has been expanded and renovated several times. The present concourses were built in 1970, along with the remodeling of the terminal. The airport itself has expanded several times from its original site and now covers 2,625 acres (10.6 km2). The airport was originally governed by the City of Des Moines' Parks Department. A separate Aviation Department was established by the city during the 1960s, and in 1982, a separate Aviation Policy Advisory Board was established. The airport was renamed the Des Moines International Airport in 1986 to acknowledge the presence of a United States Customs Service office at the airport. In 2011, the City of Des Moines transferred control from the city to the Des Moines Airport Authority.