busy airport from its inception, and by the end of 1930, it was third behind New York City and Chicago for regular daily flights with sixteen arriving and departing. Candler Field's first control tower opened March 1939. The March 1939 Official Aviation Guide shows fourteen weekday airline departures: ten Eastern and four Delta. In October 1940, the U.S. government declared it a military airfield and the United States Army Air Forces operated Atlanta Army Airfield jointly with Candler Field. The Air Force used the airport primarily to service many types of transient combat aircraft. During World War II, the airport doubled in size and set a record of 1,700 takeoffs and landings in a single day, making it the nation's busiest in terms of flight operation. Atlanta Army Airfield closed after the war. In 1942, Candler Field was renamed Atlanta Municipal Airport and by 1948, more than one million passengers passed through a war surplus hangar that served as a terminal building. Delta and Eastern had extensive networks from ATL, though Atlanta had no nonstop flights beyond Texas, St. Louis, and Chicago until 1961. Southern Airways appeared at ATL after the war and had short-haul routes around the Southeast until 1979. In 1957, Atlanta saw its first jet airliner: a prototype Sud Aviation Caravelle that was touring the country arrived from Washington, D.C. The first scheduled turbine airliners were Capital Viscounts in June 1956; the first scheduled jets were Delta DC-8s in September 1959. The first trans-Atlantic flight was a Delta/Pan Am interchange DC-8 to Europe via Washington starting in 1964; the first scheduled international nonstops were Eastern flights to Mexico City and Jamaica in 1971–72. Nonstops to Europe started in 1978 and to Asia in 1992–93. Atlanta claimed to be the country's busiest airport, with more than two million passengers passing through in 1957 and, between noon and 2p.m. each day, it became the world's busiest airport. (The April 1957 OAG shows 165 weekday departures from Atlanta, including 45 between 12:05 and 2:00 PM and 20 between 2:25 and 4:25 AM.) Chicago Midway had 414-weekday departures, including 48 between 12:00 and 2:00 PM. In 1957, Atlanta was the country's ninth-busiest airline airport by flight count and about the same by passenger count. Original Jet Terminal (1961–1980) In late 1957, work began on a new $21 million terminal, which opened on May 3, 1961. Consisting of six pier concourses radiating