From this Website…
A vast number of airmen from Australia, New Zealand, Canada, and other parts of the British Empire and its Dominions (such as South Africa, Rhodesia and so on) served in the RAF, RCAF, RAAF, or RNZAF. Even before the USA’s involvement after Pearl Harbour (7-Dec-1941) many United States nationals also swelled the ranks, usually by the simple expedient of crossing into Canada and joining the RCAF. Provided that the man concerned forsook his US citizenship, and took allegiance to the Crown, this practice was winked at by the authorities. A very large number of Canadians served in the Royal Canadian Air Force.
Specific units were formed to accommodate Australians, Canadians and New Zealanders, and such units as 460 Sqdn RAAF, 75 Sqdn RNZAF, and 428 Sqdn RCAF (to name but a few) sprang into existence. Having said that, a great number of such men also served in RAF units, the Australians soon earning a reputation for assertiveness and aggressiveness – as much on the ground as in the air!
Volunteers also came from the Caribbean and West Africa. Approximately 500 black and coloured Caribbean aircrew, as well as 6,000 ground crew, served with both Bomber and Fighter Commands during the war. About one third of these men were killed on operations and 102 of the volunteers were decorated. The most senior served as Squadron Commander with 139 (Jamaica) Squadron, based at RAF Marham.
During the celebrated “Battle of Brighton” a large contingent of RAAF airmen took on an equally large number of RAF men, during which time the Police and Military Police kept well clear. At the height of the battle, a diminutive RAF wireless-operator was engaged in close combat with a large Australian navigator. Thump! went the Ozzie’s fist against the Englishman. “Have you had enough yet you Pommie bastard?” “No” came the reply. Thump! went the fist again. “Have you had enough now you Pommie bastard?” “No” came the reply. Thump! went the fist again. “Have you had enough now?” “Yes” came the reply. “Bloody good”, said the Australian, wrapping his arm round the Englishman’s shoulders, “Let’s go and have a drink.”