The Fleetwings BT-12 basic trainer was designed and built in stainless steel. The company had some previous experience in constructing airplanes from spot-welded stainless steel and felt that the labor saved in spotwelding vs riveting could create savings relative to conventional riveted aluminum-alloy construction.
The Wikipedia article indicates that the contract was let because the Army wanted to get as many new trainers as possible into the pipeline to deal with the expected rush of student pilots.
A Design Analysis article [ PDF, 8 MiB ] , [ HTML ], written by one of the Aviation staff editors, appeared in the October, 1943, issue of Aviation. The PDF is taken from microfilmed issues, so the overall quality, especially of illustrations, is rather poor.