531st Fighter-Bomber Squadron (531st FBS) / 531st Fighter Squadron (531st FS)
U.S. Army Air Force (USAAF), 7th Air Force (7th AF), 21st Fighter Group (21st FG)

Background
On November 22, 1940 constituted as the 58th Bombardment Squadron (Light). On January 1, 1941 activated at Wheeler Field as part of the Hawaiian Air Force, later redesignated the 7th Air Force. On March 18, 1941 moves to Bellows Field. On April 29, 1941 moves to Hickam Field.

Wartime History
On December 11, 1941 returns to Bellows Field. On December 19, 1941 returns to Wheeler Field. On October 19, 1942 redesignated 58th Bombardment Squadron (Dive).

On June 18, 1943 moves to Canton Airfield.

On August 14, 1943 redesignated 531st Fighter-Bomber Squadron (531st FBS).

During December 1943 the flight echelon of A-24 Dive Bombers embarked aboard USS Nassau (CVE-16). On December 14, 1943 between 9:35am–9:44am thirteen A-24s are catapulted from the carrier then land at Makin Airfield.

On December 21, 1943 the squadron flies their first combat mission with U.S. Navy (USN) and U.S. Marine Corps (USMC) planes to hit shipping and Emidj.

On February 18, 1944 redesignated 531st Fighter Squadron (531st FS).

On March 1, 1944 moves to Bellows Field.

On April 21, 1944 moves to Kuoloa Field with P-38s.

On June 15, 1944 assigned to the 21st Fighter Group (21st FG).

On October 8, 1944 moves to Mokuleia Field with P-38s and P-51s.

On March 26, 1945 moves to South Field on Iwo Jima with P-51s

On October 10, 1946 inactivated.

References
Combat Squadrons of the Air Force World War II (1982) pages 638-639 (531st Fighter) [PDF pages 650-651]
NARA USS Nassau (CVE-16) War Diary December 1943 pages 2, 8
(Page 2) "On 15 December [1943] launched planes for Makin Island Field [Makin Airfield] from location given under air and surface patrol designated by Task Force 57 dispatch 112343 of December 1943."
(Page 8) "14 December (cont'd)
0935 In accordance with ComAirPac dispatch 080124, in position Fox (2° - 35' N, 173° - 17' E) commenced catapulting A-24 planes.
0944 Completed launching 13 A-24 planes.
1005  Commence catapulting P-39 planes.
1234 Completed launching 37 P-39 planes.
1200 Position 02° - 57' N 173° 16.5'E
1235 USS Nassau reported to ComAirPac and ComCenPac by dispatch 150005 of December 1943, the delivery of all Army planes to Makin."