The BT-12 production line inside the Fleetwings plant showing ships #9 thru #14 of a 24 ship order with serials 42-3684 to 3707 allocated. Serials 42-3708 thru 3883, which would have brought the order up to 200, were cancelled when the military decided they preferred the Vultee BT-13. Construction involved the extensive use of stainless steel, including for skin panels. The fuselage structure was made from carbon steel tube with stainless skin panels attached using "Shake-proof Fasteners" (probably what is known as quarter-turn fasteners today). The novelty of the design probably put the military off as being too different for maintenance to cope with.