the first production p-35 was delivered to the usaac in may 1937, preceded by a company owned pre-production aircraft and demonstrator, the ap-1. only 76 p-35s were built, delivery being completed in august 1938, with the 77th aircraft finished as the prototype xp-41. when it wanted further fighters in 1937, the air corps, who were unhappy with both the slow delivery of the p-35, and sale of 2pa two-seat aircraft to the japanese navy, ordered 210 curtiss p-36s.