The Armstrong Whitworth "Siskin" was one of the first fighter aircraft to be developed by the RAF after World War I. It was introduced into the RAF in 1924 and remained in service until 1932. The Siskin was a superb aerobatic aircraft and presented thrilling exhibitions of flying at every RAF display from 1925 to 1931. In 1926 the British Air Ministry sent two Siskin III's to Canada for testing by the RCAF under winter flying conditions. The RCAF eventually purchased the Mark IIIA version which were used to equip the Fighter Flight at Camp Borden and Trenton. In 1937 the Flight became No. I (Fighter) Squadron and was transferred from Trenton to Calgary in August of 1938.

A fighter design, the Siskin originally served with the RAF in this role and when acquired by the RCAF in 1927, it represented a modern state of the art design. The aircraft received a great deal of exposure in the 1930s when the RCAF formed an aerobatic display team using the type. The three-plane Siskin aerobatic team put on popular displays from coast to coast. The Siskin aircraft also formed the basis of No. 1 Fighter Squadron. The Siskin aircraft remained with this unit until the outbreak of the Second World War eventually to be replaced by modern Hawker Hurricanes in 1939. The airframes were then turned over to various technical establishments for use as instructional airframes.