665 "Air Observation Post" Squadron, RCAF was formed in England during the Second World War.

It was manned principally by Royal Canadian Artillery (RCA) and Royal Canadian Air Force (RCAF) personnel, with select British artillery pilots briefly seconded to assist in squadron formation.

The squadron was formed on 22 January 1945 at RAF Andover as an RCAF unit – albeit not in the 'Article XI' sequence of squadron numbers, but in a 'normal' British sequence – its principal role being to direct artillery fire from the air.

70 Group, RAF Fighter Command; prior to deployment to the European continent the squadron was transferred to No.

'B' Flight of 665 (AOP) Squadron, RCAF, was credited with firing the last Canadian shot of the war in Europe at Dunkirk, France, on 7 May 1945.

After V-E Day on 8 May 1945, the squadron was tasked with flying mail and passengers for First Canadian Army, while one section and its aircraft was seconded to Allied Headquarters at Frankfurt, Germany, for U.S. Intelligence duties.