The low-wing monoplane prototype for the NA-16 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 Army Air Corps for evaluation within a month of its first flight, and the design was selected for production as a basic trainer. However, the Air Corps requested the cockpits be enclosed, fairing installed on the undercarriage and the engine changed to a 600-horsepower P&W R1340 engine. The production versions (shown here) launched North American as a manufacturer of training aircraft. In all, more than 17,000 derivatives of the NA-16 were built in North American's Los Angeles, California, and Dallas, Texas, plants during the 1930s and 1940s.