The T-6 is a descendant of the NA-16 prototype, which first flew on April 1, 1935. The NA-26 was derived from it in response to the Basic Combat competition in March 1937, which it won. The USAAC ordered 180 of them under the designation BC-1, the US Navy bought 16 SNJ-1s, then 61 SNJ-2s, equipped with a more powerful engine.
Subsequently, 92 BC-1As and 3 BC-2s were produced before the aircraft's designation was changed to AT-6 (avanced trainer). The AT-6 was distinguished from its ancestor by the square shape of its wings and rudder.
It was succeeded by the NA-77, produced under the name AT-6A, powered by a Pratt & Whitney R-1340-49 Wasp. The USAAF used 1,549 of them and the US Navy 270 under the name SNJ-3. It was followed by the AT-6B, designed for aerial gunnery training, with a rear station equipped with a .30 caliber machine gun, which also introduced the R-1340-AN-1 engine. In Canada, Noorduyn Aviation produced a version of the AT-6A with this engine, the USAAF ordered 1,500 of them as the AT-16 and the RAF 2,485 as the Harvard IIB.
The "AT-6" polo shirt shown here represents an Army Air Corps aircraft stationed at Hemet-Ryan Airport in early 1943 in California.