five largest airlines (Pan American Airways, American, United, Eastern Air Lines and Transcontinental and Western Air) to begin using the new field as soon as it opened. Pan Am's transatlantic Boeing 314 flying boats moved to La Guardia from Port Washington in 1940. During World War II the airport was used to train aviation technicians and as a logistics field. Transatlantic landplane airline flights started in late 1945; some continued after Idlewild (now John F. Kennedy International) opened in July 1948, but the last ones shifted to Idlewild in April 1951. Newspaper accounts alternately referred to the airfield as New York Municipal Airport and LaGuardia Field until the modern name was officially applied when the airport moved to Port of New York Authority control under a lease with New York City on June 1, 1947. LaGuardia opened with four runways at 45-degree angles to each other, the longest (13/31) being . Runway 18/36 was closed soon after a United DC-4 ran off the south end in 1947; runway 9/27 (4,500 ft) was closed around 1958, allowing LaGuardia's terminal to expand northward after 1960. Circa 1961 runway 13/31 was shifted northeastward to allow construction of a parallel taxiway (such amenities being unknown when LGA was built) and in 1965–66 both remaining runways were extended to their present . The April 1957 Official Airline Guide shows 283 weekday fixed-wing departures from LaGuardia: 126 American, 49 Eastern, 33 Northeast, 31 TWA, 29 Capital and 15 United. American's flights included 26 nonstops to Boston and 27 to Washington National (mostly Convair 240s). Jet flights (United 727s to Cleveland and Chicago) started on June 1, 1964. Although LaGuardia was a large airport for the era in which it was built, it soon became too small. Starting in 1968 general aviation aircraft were charged heavy fees to operate from LaGuardia during peak hours, driving many LGA operators to airports such as Teterboro Airport in Teterboro, New Jersey. The increase in traffic at LaGuardia and safety concerns prompted the closure of nearby Flushing Airport in 1984. Also in 1984, to further combat overcrowding at LGA, the Port Authority instituted a Sunday-thru-Friday "perimeter rule" banning nonstop flights from LaGuardia to cities more than away; at the time, Denver was the only such city with nonstop flights, and it became the only exception to the rule. (In 1986 Western Airlines hoped to fly 737-300s nonstop to Salt Lake City