The war effort of the Royal Canadian Air Force was deeply affected by its management of the British 
Commonwealth Air Training Plan. Great numbers of Canadians served in units of Britain’s Royal Air Force, and the growth of a national Canadian air organization overseas was delayed. Nevertheless, by the German surrender, 48 RCAF squadrons were overseas, virtually completely manned by Canadian officers and men. A landmark was the formation of No. 6 (RCAF) Bomber Group of the RAF Bomber Command on 1 January 1943. It grew ultimately to 14 squadrons. It was commanded successively by Air Vice-Marshals G.E. Brookes and C.M. McEwen. 
The Bomber Command’s task was the night bombing of Germany, a desperately perilous job calling for sustained fortitude. Almost 10,000 Canadians lost their lives in this command.
Canadian airmen served in every theatre, from bases in the UK, North Africa, Italy, northwest Europe and southeast Asia. Squadrons in North America worked in antisubmarine operations off the Atlantic coast and co-operated with US air forces against the Japanese in the Aleutian Islands. At one time or another seven RCAF squadrons served in the RAF’s Coastal Command
over the Atlantic. RCAF aircraft destroyed or had a part in destroying 20 enemy submarines. In the northwest Europe campaign of 1944–45 , the RCAF deployed 17 squadrons. During the war 232,632 men and 17,030 women served in the RCAF, and 17,101 lost their lives.
Reference: http://www.thecanadianencyclopedia.ca/en/article/second-world-war-wwii/