The mid-1930s saw the beginning of the RAF expansion scheme, where many First World War airfield sites were inspected to see if they would be suitable for the new permanent stations which were planned due to the increased threat to Britain from Nazi Germany. Old Sarum Airfield was identified as suitable for becoming a permanent station, and the period between 1934 and 1937 saw the construction of new domestic, administrative and technical buildings. This increased the area of the airfield occupied by station buildings from to roughly . The flying field remained the same size.