Forces use The airfield was transferred on 12 September 1942 to the United States Army Air Forces Eighth Air Force. Debden was assigned USAAF designation Station 356. USAAF Station Units assigned to RAF Debden were: 33rd Service Group 41st and 45th Service Squadrons; HHS 33d Service Group 18th Weather Squadron 24th Station Complement Squadron 225th Anti-Aircraft Artillery Searchlight Battalion 1030th Signal Company 1063rd Military Police Company 1126th Quartermaster Company 1192nd Military Police Company 1770th Ordnance Supply & Maintenance Company 2119th Engineer Fire Fighting Platoon 546th Army Postal Unit 4th Fighter Group With the transfer of the airfield and the entry of the United States into the war, Americans serving in the RAF Eagle squadrons were transferred into the American ranks, with 71, 121 and 133 RAF Eagle Squadrons becoming the 4th Fighter Group. The group was under the command of the 65th Fighter Wing of the VIII Fighter Command. Aircraft of the group were identified by red around their cowlings and tails. The group consisted of the following squadrons: 334th Fighter Squadron (QP) (Former 71 Squadron) 335th Fighter Squadron (WD) (Former 121 Squadron) 336th Fighter Squadron (VF) (Former 133 Squadron) The 4th Fighter Group destroyed more enemy aircraft in the air and on the ground than any other fighter group of the Eighth Air Force. The group operated first with Supermarine Spitfires but changed to Republic P-47 Thunderbolts in March 1943 and to North American P-51 Mustangs in April 1944. On numerous occasions the 4th FG escorted Boeing B-17 Flying Fortress and Consolidated B-24 Liberator bombers that were attacking factories, submarine pens, V-weapon sites, and other targets in France, the Low Countries, or Germany. The group went out sometimes with a small force of bombers to draw up the enemy's fighters so they could be destroyed in aerial combat. At other times the 4th attacked the enemy's air power by strafing and dive-bombing airfields. They also hit troops, supply depots, roads, bridges, rail lines, and trains. The unit participated in the intensive campaign against the German Air Force and aircraft industry during Big Week, 20–25 February 1944. They received a Distinguished Unit Citation for aggressiveness in seeking out and destroying enemy aircraft and in attacking enemy air airfields during the period 5 March – 24 April 1944. The 4th FG flew interdictory and counter-air missions during the invasion of Normandy in June 1944 and supported the airborne invasion of the