Most units of the Royal Air Force are identified by a two character alphabetical or alpha- numeric combination squadron code. Usually, that code is painted on the aircraft belonging to that unit. The squadron code is usually presented along with an individual letter or character to form a call sign for the particular aircraft. Location of the call sign combination has usually been on the rear fuselage next to the RAF roundel.
In instances when an unusually large numbers of aircraft comprise the squadron, multiple squadron codes have been used.
Other air forces, especially those from other Commonwealth countries, have often used similar systems of identification. During the Second World War, when units from other air forces were attached to the RAF – such as the Article XV squadrons (also known as "400 series squadrons") – their squadron codes were often changed, to avoid confusion with RAF units.
Data from: Flying Units of the RAF
* = RAAF/RCAF unit that was not under RAF operational control.
Radio call signs
Transport Command 'O' series
Transport Command RAF applied the following three letter call-signs to its aircraft from 1944. Individual aircraft were given letter suffixes, making the code a four letter sequence.
Data from: Flying Units of the RAF
Transport Command 'MO' series
- Lake 1999, p. 294-303.
- Australian War Memorial, n.d., The Royal Australian Air Force Squadron Codes (access: 27 June 2019).
- Lake 1999, p. 303-304.
- Bowyer, Michael J.F. and John D.R. Rawlings. Squadron Codes, 1937-56. Cambridge, Cambridgeshire, UK: Patrick Stephens Ltd., 1979. ISBN 0-85059-364-6.
- Delve, Ken. The Source Book of the RAF. Shrewsbury, Shropshire, UK: Airlife Publishing, 1994. ISBN 1-85310-451-5.
- 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, 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, C.G. RAF Squadrons, a Comprehensive record of the Movement and Equipment of all RAF Squadrons and their Antecedents since 1912. Shropshire, Shropshire, UK: Airlife Publishing, 1988 (second edition 2001). ISBN 1-85310-053-6.
- Moyes, Philip J.R. Bomber Squadrons of the RAF and their Aircraft. London: Macdonald and Jane's (Publishers) Ltd., 2nd edition 1976. ISBN 0-354-01027-1.
- Rawlings, John D.R. Coastal, Support and Special Squadrons of the RAF and their Aircraft. London: Jane's Publishing Company Ltd., 1982. ISBN 0-7106-0187-5.
- Rawlings, John D.R. Fighter Squadrons of the RAF and their Aircraft. London: Macdonald & Jane's (Publishers) Ltd., 1969 (2nd edition 1976, reprinted 1978). ISBN 0-354-01028-X.
- RAF Squadron Codes during World War II
- Australian War Memorial, n.d., The Royal Australian Air Force Squadron Codes.
- a list of current squadrons from the RAF website
- RAF - University Air Squadrons
- UBAS - University of Birmingham Air Squadron
- UGSAS - Universities of Glasgow and Strathclyde Air Squadron
- BUAS - Bristol UAS
- CUAS - Cambridge UAS
- EMUAS - East Midlands UAS
- ESUAS - East Scotland UAS
- LUAS - Liverpool UAS
- MASUAS - Manchester and Salford UAS
- ULAS - University of London Air Squadron
- OUAS - Oxford UAS
- SUAS - Southampton UAS
- Southampton University Air Squadron - Wiki
- UWAS - Wales UAS
- YUAS - Yorkshire UAS