The figures quoted appear to only include those aircrew that trained at some time in Canada. In fact the scheme included many other smaller locations and some countries undertook training programs outside the scheme, so this figure is somewhat less than the numbers trained worldwide under the BCATP and its various derivatives as well as the national programs undertaken by countries of the Commonwealth.
According to Alan Stephens ("The Royal Australian Air Force"), under the scheme, the UK was to recruit and train four-ninths of the RAF's annual aircrew requirements. The remaining five-ninths was to be apportioned across the Dominions as follows:-
Australia 36%
Canada 56%
New Zealand 8%
The Royal Australian Air Force trained 27,899 men through the Empire Air Training Scheme, and a further 11000 or so outside of that scheme. If Miloshes figure of 9606 is correct for the RAAF contribution to the Canadian program, then a substantial amount of training was completed outside of Canada (though his figures dont seem to gel completely with my understanding of the proportions) Prior to the scheme the RAAF had trained about 50 pilots per year, plus there were 450 Australian pilots serving in the RAF directly from 1939. Seven-ninths of the RAAF's intake were trained in Australia (all Elementary and some Advanced) with the remaining two-ninths trained in Canada (Advanced). The RAAF had to provide airfields, aircraft, instructors etc to allow this all to happen
In Australia the scheme was simply known as the EATS scheme. By 1945, more than 37,500 Australian aircrew had completed training either within or outside of the EATS; a majority of these, over 27,300, graduated from schools in Australia directly under the EATS, with some of that number receiving advanced training in Canada. Many others were also were trained under article 15, the majority of the European deployed personnel received their training directly in Europe, presumably in England. The duration of World War II saw 15,746 RAAF pilots, navigators, wireless operators, gunners and engineers sent to British squadrons and 11,641 to Australian squadrons from the EATS, and a further 11000 or so trained outside of EATS for direct use by the RAAF
Perhaps some of the confusion arises because schemes outside Canada were not actually known as BCATP with a number of countries retaining some home based training outside of the EATS schemes as indicated in the Australian experience that I have outlined above. In South Africa, the scheme was termed the Joint Air Training Scheme (JATS). Under this scheme, 38 South African–based air schools would be employed to train Royal Air Force, SAAF and other allied air and ground crews. This scheme during its five year existence, was ultimately to turn out a total of 33,347 aircrew, including 12,221 SAAF personnel. Not all of this number were trained under the BCATP.
The Rhodesian Air Training Group (RATG), operating 1940–1945, was set up as part of the overall Commonwealth Air Training Plan. Again, some of its numbers need to be considered as a separate subtotal to the Canadian based schools principally because some personnel completed their advanced training outside of Canada, and also because some personnel were trained outside the BCATP scheme. The trainees came mainly from Great Britain but also from Australia, Canada, South Africa, New Zealand, USA, Yugoslavia, Greece, France, Poland, Czechoslovakia, Kenya, Uganda, Tanganyika, Fiji and Malta. There were also pupils from the Royal Hellenic Air Force in training. Over 7,600 pilots and 2,300 navigators were trained by the RATG during the war.
In the case of Canada, at the conclusion of the war, over 167,000 students, including over 50,000 pilots, trained in Canada under the program from May 1940 to March 1945. While the majority of those who successfully completed the program went on to serve in the RAF, over half (72,835) of the 131,553 graduates were Canadians. I do not have figures on how many Canadians were trained outside of the BCATP.
In the US CATPs were set up after so many US citizens crossed the border prior to December 1941, to undergo training. This was a cause for considerable embarrassment for both the Canadians and the Roosevelt administration. Prior to Pearl Harbor, training centres were made available for the RAF; by war's end, 16,000 RAF aircrew were trained in the United States. After Pearl Harbor, 1,759 American members of the RCAF transferred to the armed forces of the United States, another 2,000 transferred later on, and about 5,000 completed their service with the RCAF
I don't have final figures for training undertaken directly in the UK, but it may be as high as 22000 aircrew every year.
During the war, the RNZAF contributed 6940 personnel to the BCATP, including 2,743 fully trained pilots to serve with the RAF in Europe, the Middle East, and Far East. More than 2,700 wireless operator/air-gunners, 1,800 navigators, and 500 bombardiers passed through the Initial Training Wing before proceeding to Canada. Of the 131,000 trainees who graduated in Canada under the Commonwealth Air Training Plan, New Zealanders formed 5.3%.
Another 1,521 pilots and an unknown number of other aircrew completed their training in New Zealand outside the BCATP, and were retained in country; either as instructors, staff pilots, or manning operational squadrons formed during the latter half of the war. My best estimate is that about 3800 personnel were given some form of aircrew training outside the EATS scheme in New Zealand.
In 1940, before the British Commonwealth Air Training Plan was fully developed, New Zealand also trained 183 observers and 395 air gunners for the RAF. From 1943 onwards, the training of wireless operator/air gunners, and navigators was carried on in New Zealand for Pacific operations.
Clearly therefore, the figures quoted for the BCATP, whilst representing a substantial portion of the Commonwealth air training shemes does not represent the total training program.