The Deputy Chief of the Air Staff (DCAS) was a senior appointment in the Royal Air Force. The incumbent was the deputy to the Chief of the Air Staff. The post existed from 1918 to 1968 or 1969. Today, the Chief of the Air Staff's deputy is titled as the Assistant Chief of the Air Staff.
The post was created on 3 January 1918 as part of the preliminary work before the creation of the RAF and the incumbent sat on the Air Council. However, with the establishment of the RAF on 1 April 1918, the Deputy Chief of the Air Staff was removed from the Air Council. From the mid-1920s to 1938, the Deputy Chief of the Air Staff was double-hatted as the RAF's Director of Operations and Intelligence. In 1930, when Trenchard stepped down as Chief of the Air Staff, the Deputy Chief of the Air Staff was once again appointed to the Air Council.
Holders of the post included: