The Boeing T-43 was a modified Boeing 737-200 used by the United States Air Force for training navigators. Informally referred to as the Gator (an abbreviation of "navigator") and "Flying Classroom", nineteen of these aircraft were delivered during 1973 and 1974. Several were later converted to CT-43As as executive transports. The T-43 was retired in 2010 after 37 years of service.