No. 660 Squadron was a Royal Air Force Air Observation Post squadron associated with the 21st Army Group during World War II. Numbers 651 to 663 Squadrons of the RAF were Air Observation Post units working closely with Army units in artillery spotting and liaison. A further three of these squadrons, 664–666, were manned with Canadian personnel. Their duties and squadron numbers were transferred to the Army with the formation of the Army Air Corps on 1 September 1957.
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Flintham, Vic and Andrew Thomas. Combat Codes: A full explanation and listing of British, Commonwealth and Allied air force unit codes since 1938. Shrewsbury, Shropshire, UK: Airlife Publishing Ltd., 2003. ISBN 1-84037-281-8.
Halley, James J. The Squadrons of the Royal Air Force & Commonwealth 1918–1988. Tonbridge, Kent, UK: Air Britain (Historians) Ltd., 1988. ISBN 0-85130-164-9.
Jefford, Wing Commander C.G., MBE, BA, RAF(Retd.). RAF Squadrons, a Comprehensive record of the Movement and Equipment of all RAF Squadrons and their Antecedents since 1912. Shrewsbury, Shropshire, UK: Airlife Publishing Ltd., 1988 (second edition 2001). ISBN 1-85310-053-6.