Hartsfield–Jackson Atlanta International Airport , also known as Atlanta Hartsfield–Jackson International Airport, Atlanta Airport, Hartsfield, Hartsfield–Jackson and, formerly, as the Atlanta Municipal Airport, is the primary international airport serving Atlanta, Georgia, United States. The airport is located south of the Downtown Atlanta district. It is named after former Atlanta mayors William B. Hartsfield and Maynard Jackson. ATL covers of land and has five parallel runways. Hartsfield-Jackson has been the world's busiest airport by passenger traffic since 1998, except when it briefly lost its title in 2020 due to the effect of the COVID-19 pandemic in the United States but regained it in 2021. Hartsfield–Jackson is the primary hub of Delta Air Lines. With just over 1,000 flights a day to 225 domestic and international destinations, the Delta hub is the world's largest airline hub and is considered the first mega-hub in America. In addition to hosting Delta's corporate headquarters, Hartsfield–Jackson is also the home of Delta's Technical Operations Center, which is the airline's primary maintenance, repair and overhaul arm. Aside from Delta, Hartsfield-Jackson is also a focus city for low-cost carriers Frontier Airlines and Southwest Airlines. The airport has international service within North America and to Latin America, Europe, Africa, Middle East and East Asia. The airport is mostly in unincorporated areas of Clayton County, but it spills into the city limits of Atlanta, College Park, and Hapeville, in territory extending into Fulton County. The airport's domestic terminal is served by MARTA's Red and Gold rail lines. History Candler Field/Atlanta Municipal Airport (1925–1961) Hartsfield–Jackson began with a five-year, rent-free lease on that was an abandoned auto racetrack named The Atlanta Speedway. The lease was signed on April 16, 1925, by Mayor Walter Sims, who committed the city to develop it into an airfield. As part of the agreement, the property was renamed Candler Field after its former owner, Coca-Cola tycoon and former Atlanta mayor Asa Candler. The first flight into Candler Field was September 15, 1926, a Florida Airways mail plane flying from Jacksonville, Florida. In May 1928, Pitcairn Aviation began service to Atlanta, followed in June 1930 by Delta Air Service. Those two airlines, later known as Eastern Air Lines and Delta Air Lines, respectively, would both use Atlanta as their chief hubs. The airport's weather station became the official location for Atlanta's weather observations on September 1, 1928, and records by the National Weather Service. Atlanta was a