The turf acres of Newmarket Heath offered a ready made landing ground for aircraft and was first so used during the 1914 1918 War. The adjacent racecourse was undoubtedly an attraction and during the inter-war years many private owners landed on the heath to attend race meetings. In 1938 the Air Ministry took an interest in the site as a satellite base for Mildenhall and on September 1, 1939 began transferring over No. 99 Squadron's Wellingtons, apparently without notifying the Clerk of the Course! This was approximately 300 acres north of the Beacon Course and Cambridge Hill providing one of the longest grass landing and takeoff runs available at the time - 2,500 yards in an east-west direction. Accommodation for air and ground crews was in the racecourse administration buildings, the grandstand and requisitioned local housing until new huts were erected.
No. 99 conducted operations from Newmarket until March 1941 when it moved to the new airfield at Waterbeach. During the winter of 1940-41 and the following spring, Newmarket was often used as an alternative airfield by Stirlings from Oakington. Whitley's appeared but these were used with a number of Lysanders for `special operations' over occupied countries delivering agents and equipment to aid resistance forces. No. 1419 Flight carried out this mission becoming No. 138 Squadron in August 1941 before moving to Graveley in December. With an increasing demand for this service, No. 3 Group formed a second squadron, No. 161, at Newmarket in the following February but it moved within weeks to Stradishall.
During 1941-42, a hard taxiway was put down along the northern perimeter to link a total of 24 loop-type aircraft standings. Three T2 hangars were erected on the technical site, on the north-east side, and a Bl to the east of the operational buildings site on the south side at the eastern end of Beacon Course. Two Bl hangars were also erected, possibly at a later date, on the north-west side of the airfield near Portland Farm and to the west of the bomb store. Additional domestic sites were dispersed to the northeast on the outskirts of the town.In November 1942, No. 75 Squadron arrived while runways were laid at Mildenhall and operated from Newmarket Heath until June 1943 when the new Class A station at Mepal offered a better environment for the heavy Stirlings. With several new airfields with hardened runways coming into use, Newmarket was relegated to a support role.