The last prototype airplane from North American Aviation was the NA-16 trainer. It was initially built at North American's General Aviation Manufacturing Corp., located at the Curtiss-Caproni plant at Dundalk, Md. Later, it was produced in California. The low-wing monoplane had open cockpits in tandem and a fixed, unfaired undercarriage. Made mostly of metal, but with some fabric on the rear fuselage, it was submitted to the U.S. Army Air Corps for evaluation within a month of its first flight.
The design was selected for production as a basic trainer, although the Air Corps requested that the cockpits be enclosed, fairing be installed on the undercarriage and the engine changed to a 600-horsepower Pratt & Whitney R1340 engine. With these modifications, and a new designation of NA-18, the prototype was eventually sold to Argentina.
The production versions launched North American as a manufacturer of training aircraft, starting with 267 BT-9s and 340 BC-1 "basic combat" trainers. In all, more than 17,000 derivatives of the NA-16 were built including 13,685 of the famous T-6/SNJ series built at North American's Los Angeles, Calif., and Dallas, Texas, plants during the 1940s.