RAF Middle Wallop was originally opened as a training school, home of the 15th Service Flying Training School flying Oxfords and Masters, who arrived in June 1940. The airfield and base had taken 18 months to build.
With the fall of France and the outbreak of the Battle of Britain, however, the airfield was soon in demand for operational purposes, and it became a sector operations HQ (Y Sector) for 10 Group. Both fighters and light bombers were based here.

‘Y’ sector had responsibility for defending the naval base of Portland, as well as the Supermarine aircraft factory on Southampton and the Isle of Wight. After the beginning of the Blitz in September 1940 its duties extended to defending the cities on the South Coast.

Squadrons stationed here included 236 Squadron (flying Blenheim light bombers), 238 Squadron (Hurricanes) and 401 (RCAF – Hurricanes) from June 1940, 501 Squadron (Hurricanes), 609 Squadron (Spitfires) and 604 Squadron (Blenheims) in July, 222 Squadron (Spitfires) in August, and 238 Squadron (Hurricanes) and 23 Squadron (Blenheims) in September. 604 squadron was later equipped with Beaufighter nightfighters flown by Sqn Ldr John Cunningham.

609 Squadron was perhaps the most famous squadron to be based at RAF Middle Wallop during the Battle, being the first to down 100 enemy aircraft. On August 13, the squadron intercepted a raid over Portland. They claimed at least 13 enemy aircraft downed and several more ‘probables’. On the next day the Luftwaffe visited their revenge – a single German bomber dropped five bombs on the airfield, damaging hangars four and five. Three airmen died as they were trying to close the vast doors to protect the aircraft inside.

RAF Middle Wallop was also used by the United States Army Air Forces Ninth Air Force as IX Fighter Command Headquarters beginning in November 1943. Today the airfield is the home of the Army Air Corps.