Hi Pauline - Wing airfield was used mainly as an Operational Traing Unit flying Wellingtons during WW2. A few bombing operations were undertaken by the OTU airplanes in support of the 1,000 bomber raids. Towards the end of the course crews would also fly on leaflet dropping missions over France. At the end of the war many ex-POWs were flown into Wing on their return to the UK.
The airfield closed to flying in 1946 and I know of no further activity after that date that would explain the US presence other than perhaps on some sort of exercise.