The Royal Air Force returned to Upwood Airfield in January 1937 when Squadrons 52 and 63, equipped with Hawker Hind and Audax bi-planes, were located there. Squadrons 90 and 53, equipped with Bristol Blenheims, replaced 52 and 63 Squadrons by February 1940 - their main mission to train RAF personnel for bombing missions. These two units later merged to form 17 Operational training Unit (OTU).

In September 1940, No.11 Beam Approach Training (BAT) Flight unit was formed at Upwood, with emphasis on bad weather and night flying training.

Joseph Jakobs was parachuted in to spy on RAF Upwood in Jan 1941. Breaking his ankle on landing he was easily captured and eventually imprisoned in the Tower of London becoming the last known person to be executed in the Tower.

By April 1943 the airfield came under No. 8 PFF (Pathfinders) Group but as the grass runways were frequently waterlogged, upgrading work was required.

Three new concrete runways were constructed by October 1943, allowing the first of the Pathfinder Squadrons, No. 139 (Jamaica), to use the airfield the following January. From this time forward, Upwood Airfield was home to 139 Squadron equipped with Mosquitoes as well as 156 Squadron with Lancaster bombers.

At the end of the Second World War, 156 Squadron was relocated at Wyton whilst 139 Squadron remained at Upwood until February 1946. After this it was used as a training centre for some time and was later leased to the USAF. It is now closed, although USAF has retained a medical facility on site. The housing has been sold and some of the hangars have been converted for use by Turbine Motor Works Ltd. There are ambitious plans to redevelop the rest of the base.