As World War II arrived, the U.S. military chose the Wasp Junior for the Vultee BT-13 Valiant and North American BT-14 basic training aircraft and for the Vought OS2U Kingfisher observation floatplane. Military versions of existing Wasp Junior-powered civilian aircraft were also produced, such as the military derivatives of the Beech 18, Beech Staggerwing, Grumman Goose, and Howard DGA-15. The Wasp Junior also powered some versions of the British Avro Anson and Airspeed Oxford twin-engined trainers.