40 Squadron Royal Flying Corps was formed on 26 February 1916 at Fort Grange, Gosport, equipped with a mixture of training types.

In July that year it received its intended operational mount, the Royal Aircraft Factory F.E.8, a single-seat pusher configuration fighter, being the first squadron equipped with the F.E.8.

[5][6] On 9 March 1917, a patrol of nine 40 Squadron F.E.8s were attacked by a formation of German fighters from Jasta 11, led by Manfred von Richthofen.

[5] The better performance of the Nieuport allowed 40 Squadron to be more effective, flying offensive patrols, including attacks on German Observation balloons.

[3][6] From April 1917, as part of the 10th Wing RFC, it flew in support of the British offensive at the Battle of Arras,[9] destroying four balloons (and damaging four more) in a low-level attack on 2 May, and seven more on 7 May.

[3] After the Munich Agreement in 1938, with the prospect of war with Nazi Germany becoming more likely, plans were made to forward deploy the Battle-equipped squadrons of 1 Group to France as the Advanced Air Striking Force.

This was to bring the short-range Battles within range of German industrial targets in the Ruhr, and the aircraft were not intended to operate in direct support of the British or French armies.

[24][25][22] The squadron flew its Battles to Bétheniville, its pre-arranged base in France, on 2 September 1939, the eve of the British declaration of War against Germany.

[22][26] Experience showed that the Battle was obsolete, and the squadrons of the Advanced Air Striking Force were mainly employed on training duties.

[34] After the fall of France, attacks switched to barges waiting at Channel ports for the planned German invasion of Britain.

[46] After the Allied victory in the battle, the squadron was moved westwards to aid attacks on the supply lines of the retreating German and Italian forces.

[3][19] The squadron re-equipped with Consolidated Liberators in March 1945,[3] flying its last mission of the war on the night of 25/26 April 1945, against marshalling yards North West of Salzburg, Austria.

The Soviets lifted the blockade in May 1949, with 40 Squadron withdrawn from the airlift in July 1949, operating from RAF Bassingbourn from its return to Britain until it was disbanded on 15 March 1950.

In 1954, the Coningsby Wing was broken up to allow the airfield to be redeveloped to accommodate V-bombers, and as a result, 40 Squadron moved to RAF Wittering in February 1954.