In one respect however, it was a step backwards from its immediate predecessor, the BT-14, with which it is often confused, in that the earlier straight wings were used with the result that in RCAF service, when compared to the later and more powerful Harvard II it was flown alongside, it had different handling characteristics and lower performance.

The remaining 119 undelivered aircraft were bought up by the British Purchasing Commission and transferred to the Royal Canadian Air Force (RCAF) for the British Commonwealth Air Training Plan between August and September 1940,[2] and all were operational by November[5] The type was named the Yale Mk.I[note 1] following British naming practice of naming trainers after education institutions and US-supplied aircraft after American locations, in this case, Yale University, and were used initially as intermediate pilot trainers taking pilots from the de Havilland Tiger Moth and Fleet Finch to the much faster and more complex North American Harvard,[4] until this category was dispensed with as being unnecessary.

The NAA-64s captured from the French were used by the German Luftwaffe for all types of flight training, from basic flying to advanced fighter tactics.

Dive bomber schools and target tug units and even combat squadrons all used the NAA-64, as they were designated by the Luftwaffe, from the tail markings of the French examples.

Simmons bought 39 Yales in 1946,[25] along with seven Fairey Swordfish and a Westland Lysander[26] and kept them on his farm until he died in 1970.