The Germans overran half of the entire country in a matter of weeks. Their attack against civilians was clearly a rehearsal for their coming attack in the west. The scale and speed of modern war had shifted an order of magnitude.

Germany's attack on Poland revealed they had also trained the thousands of pilots, air crew and ground crew required to fly, navigate, defend and maintain their brand new Luftwaffe. They had conducted all this training in secret.

Alarmed, Whitehall military planners knew it took about two weeks to build a modern aircraft. Contrarily it took around a full year to train its pilot and crew. The coming war was an air war, Churchill realised. Britain's short-term challenge was to survive. The Allies were outnumbered two-to-one in aircraft and were well behind - by at least a year or even two years - in pilot and aircrew training.

If the Royal Air Force was to mount a tactical fighter defence in 1940 and 1941 and - if Britain was eventually to strike back against Germany and gain air superiority over Europe - to fly a strategic heavy bombing campaign in 1942 and 1943, they needed vast numbers of pilots and aircrew.

Britain also needed as many pilots again to fly the immense logistics required to deliver the planes, spares, equipment, aviation fuel, ammunition and bombs, food and support personnel continuously to its frontline fighter and bomber bases throughout the coming war, the minister for munitions and the secretary of state, Winston Churchill calculated.

UK factories could turn out 2250 aircraft a month. Therefore, Britain required 15,000 to 20,000 pilots a year. In 1939, Britain had just eight flying schools with the prospect of forming just 10 more. To train pilots at that scale required some 90 flying schools, an impossible task.

Britain had only one option. It turned to the dominions of its global empire - in particular, Australia, Canada, and New Zealand. In September and October, cables flew between Whitehall in London and governments in Ottawa, Canberra, and Wellington.

The Empire Air Training Scheme or EATS was born. The first EATS conference was held in Ottawa in October. Representing Australia was our minister for air and civil aviation, James Fairbairn.

Australia's prime minister Robert Menzies argued that training Australian pilots to defend Britain would be in Australia's longer-term defence interests. A substantial modern RAAF would "have great mobility and striking power," he reasoned.

In a radio broadcast on October 11, 1939, Menzies told Australians "The British, Canadian, Australian and New Zealand governments have agreed to combine in the training of the skilled personnel of a vast air force on a scale that is literally without precedent."

In 1939, Australia had only about 160 training aircraft. Most were privately owned in aeroclubs in Wagga, Amberley and Geraldton. The Australian government immediately commandeered all flying clubs and aerodromes.

The RAAF had only one flying training school, Number One Flying Training School at Point Cook near Melbourne. Point Cook had 16 flying instructors and was graduating just 20 or so pilots every six months. Overall Australia was training only around 100 pilots a year.

The EATS Agreement committed Australia, Canada and New Zealand to train and graduate over 50,000 aircrew every year - 20,000 pilots and 30,000 aircrew - apportioned on a population basis. Australia needed to graduate over 300 pilots every month; Canada, 80. This was a 30-fold increase.

RAAF planners calculated that by early 1943 they needed to develop 12 elementary and eight advanced flying training schools and 11 special schools to teach flight navigation, wireless operations, gunnery and bomb-aiming.

Southern Rhodesia (now Zimbabwe) offered aerodromes as training facilities if Britain supplied the trainers and aircraft. Rhodesia formed the Rhodesia Air Training Group. By mid-1940, Australia sent around 40 trainees a month to Rhodesia. My father, Frank Evans, was one of the 670 Australians who trained in an Elementary Flying School in Africa.

The Australian military predicted as early as 1939 that if Germany invaded Holland, Japan might attempt to invade the Dutch East Indies (today's Indonesia) to seize its oil reserves. Therefore, Fairbairn and Menzies stipulated that a large contingent of Australian pilots trained here would stay in Australia to defend us against the looming threat from Japan.

Australia agreed to meet the costs of upgrading civilian aerodromes, and building new airfields, huts, and flight school buildings if initially Britain supplied the trainer aircraft and flight trainers. In the first round, civilian pilots instructed new RAAF trainees.

Under EATS, Australia also committed to manufacturing the engines, bodies and spares for a range of trainer aircraft, single-engine Tiger Moths, North American Harvards, and Wirraways, and multiple-engine Avro Ansons, and Airspeed Oxfords. To seed this new industry, we imported whole aircraft, bodies, engines and spares. Engineers arrived from the UK and Canada to advise us on designing and building new aviation factories. At the time, Australia had never manufactured a motor vehicle. The word "Wirraway" was well-named. "Wirraway" is the Australian Aboriginal word for challenge.

The whole country became air-minded. Bright recruitment brochures painted a glowing picture of the benefits of joining the RAAF. During the First World War, the infantryman's battleground was relatively static and deadly. For the Second World War, applicants would be trained to fly modern aircraft. They would also gain the skills for a career as a professional pilot.

Applicants had to be at least 18 years old. They had to have stayed at school long enough to have earned at least an intermediate certificate with basic studies in mathematics and at least one other STEM subject: engineering or science. These subjects were required for them to cope with classes in flight theory, meteorology and navigation.

This educational requirement quickly became a problem for RAAF planners. Most young men had left school early during the Depression. By 1939, only 16 per cent of young Australian men held an intermediate certificate or better. So the RAAF set up refresher courses in mathematics, trigonometry and physics. For support air crew, they lowered the needed qualification.

The financial incentives were considerable. Pay rates were much higher than for the Australian Army or Navy. The RAAF promised to offer commissions to around a third of graduates. Commissioned officers received 17 shillings a day, and their wives received four-pounds-five-shillings a week. By comparison, a private in the Australian Army received just five shillings a day.

The medical requirements were stringent. Applicants had to be physically fit and have excellent eyesight. They were subjected to a battery of X-rays and general pathology tests. If they had broken any bones in the past these were X-rayed carefully to ensure their healing was successful. Candidates were given a protracted mercury test to ensure they had sufficient breathing and lung capacity. The medical examination took an entire day.

The RAAF also invited young women to join the Women's Air Training Corp, or the Women's Auxiliary Australian Air Force where they were trained in aircraft maintenance, flying transport logistics, and airbase support roles.

Once in Britain, Australian and Canadian pilots could choose from being more experienced individually or in small groups throughout RAF squadrons, or they could join all-Australian and all-Canadian squadrons. Whichever they chose, they were under the command of the RAF.

In Britain, pay equity became an issue. RAF pay rates for pilots were slightly less than Australian and Canadian salaries. The Australian and Canadian governments agreed to make up the difference if pilots returned home after completing a tour of war service in Britain.

As soon as any pilot experienced any air-sickness or blacked out, even if momentarily, they were immediately scrubbed. Pilots did not have pressure suits during the Second World War. As different variants of single-engine fighters, such as the Spitfire, Hurricane and Kittyhawk, became more powerful and subjected their pilots to even higher Gs, the numbers of fighter pilots scrubbed rose from one-in-three to as high as one-in-two.

Scrubbed pilots were offered a choice. They could continue their pilot training on multiple-engine aircraft such as the Anson and Oxford, and fly medium and heavy bombers or the Dakota-DC3. Or they could re-train as navigators, wireless-operators, observers and air-gunners. Most elected to continue their pilot training.

During the entire First World War, Australia trained a total of just under 160 pilots. When the Second World War broke out in 1939, the RAAF had 450 pilots dispersed throughout RAF squadrons in Britain, far more than in the entire RAAF back in Australia.

The Empire Air Training Scheme took in over 51,000 recruits overall during the war. Over 37,500 trained and graduated in Australia. These comprised 15,400 pilots, 9800 navigators and 13,500 air-gunners. 9600 Australians were trained in Canada; around 650 in Rhodesia.

Training accidents were common. Over 300 EATS trainees were killed in flying accidents: 230 in Australia, 65 in Canada and almost 20 in Rhodesia.

The casualties were enormous. Fighter pilots had a saying, "Why don't we do up our top buttons? We don't live long enough." Pilots believed they had a less-than-50 per cent chance of completing a tour. Their estimate was correct.

Of the 22,000 Australian pilots and aircrew who served in RAF units all over the world during the war, more than 11,200 were killed or listed as missing in action, a casualty rate of one in two. Most were killed in the heavy massed Allied night-and-day bombing raids over Germany in 1943 and 1944. Their deaths amounted to around a quarter of all Australians killed during World War 2.

The Australian Parliament inaugurated the Australian Air Force 100 years ago on March 31, 1921. In August the British Parliament added the suffix "Royal" and the AAF became the RAAF. The RAF was the first airforce in the world. The RAAF was the second. When it was formed and up until the end of the Second World War the RAAF was essentially an extension of the RAF. Its insignia was the same red circle with a blue roundel of the RAF.

In 1939, the RAAF had 4000 personnel. Just five years later in 1945 its ranks had grown to 120,000, over 30 times, the same increase required by the Empire Air Training Scheme. The red circle of its insignia became a red kangaroo. The RAAF had its own command structure and identity.