In late 1943 the United States Army Air Forces acquired usage rights to the airport. It was placed under the jurisdiction of the IV Fighter Command. The 481st Night Fighter Operational Training Group (NFOTG) used the facility, named Delano Army Airfield, as part of the Army Air Forces Night Fighter School which had transferred from Florida to Hammer Field, California. Delano was used as an auxiliary training airfield. The school operated a combination of modified Douglas A-20 Havocs for night fighter operations, designated P-70, and new prototype YP-61 Black Widow purpose-built night fighters.