O-47 light observation aircraft, along with B-25 Mitchell and B-34 Lexington medium bombers equipped with antisubmarine radar were used to fly anti-sub patrols over the Atlantic coast and the eastern Gulf of Mexico.

In September 1943, the P-70s were replaced by the purpose-built Northrop P-61 Black Widow night fighter and the 420th NFS was moved to Dunnellon Army Air Base in August 1943.

On 6 September 1944, the 904th Army Air Forces Base Unit (Fighter), was assigned to Kissimmee AAF with a mission of testing tactics, techniques and equipment.

With the end of the European War in May 1945, the pace of flying slowed down and in June 1945, orders were received from Orlando AAB that Kissimmee AAF would be closed.

The base was declared as surplus and was turned over to the War Assets Administration (WAA) for disposal and return to civil use by the end of the year.