Class A airfields were World War II (WW2) military installations constructed to specifications laid down by the British Air Ministry Directorate General of Works (AMDGW). Intended for use by heavy bombers and transports, they were the standard airbase design for the Royal Air Force (RAF) as well as United States Army Air Forces (USAAF) units operating from the United Kingdom (UK).
Upon the entry of the United States into WW2, a number of Royal Air Force Class A bases were transferred to the U.S. Eighth Air Force for use as heavy bomber bases, with the RAF units formerly occupying them being redeployed to other RAF bomber airfields, and U.S. Army Engineer Units constructed more airfields to this standard, or brought earlier airfields up to this specification by lengthening runways, etc.[1] Many units of the U.S. Ninth Air Force also flew from Class A airfields. The term Class 'A' came about because, quite often, the resultant aerial shot of the crossed runways would look like the capital letter A.[2]