The Boeing T-43 is a modified Boeing 737-200 that was used by the United States Air Force for training navigators, now known as USAF combat systems officers from 1973 to 2010. Informally referred to as the Gator (an abbreviation of "navigator") and "Flying Classroom", nineteen of these aircraft were delivered to the Air Training Command (ATC) at Mather Air Force Base, California during 1973 and 1974. Two additional aircraft were delivered to the Colorado Air National Guard at Buckley Air National Guard Base (later Buckley Space Force Base) and Peterson Air Force Base, Colorado, in direct support of cadet air navigation training at the nearby U.S. Air Force Academy. Two T-43s were later converted to CT-43As in the early 1990s and transferred to Air Mobility Command (AMC) and United States A