sentences:  From 1962 to 1963 further additions were made to the airport, perhaps brought about by the new passenger planes.In 1964, Northeast Airlines was operating nonstop service to New York John F. Kennedy Airport with four-engine Douglas DC-6B propliners in addition to other flights to other destinations operated with DC-3 aircraft.Northeast then began the first turboprop service to Keene with the 48-passenger Fairchild Hiller FH-227 in 1966.