The Model 80 transport series, built for Boeing Air Transport, started with the 12-passenger Model 80 in 1928. They evolved into the 18-passenger Model 80A, the open cockpit Model 80B, and a deluxe executive transport, the Model 226. The first female flight attendants served passengers on the Model 80A. These were registered nurses, capable of calming travelers and clearing fences when the plane landed short of a runway.