My emphasis
More like 15,000. 1,500 is barely two battalions.
However, that is divisional strength, which is considerably larger with artillery, support services, etc than the much smaller infantry elements in a division.
Ask, and ye shall receive.
Australian Military Aviation and World War One
Although Australian Military aviation can be traced to flights made by a Royal Engineer Balloon Section at the Sydney Agricultural Ground on 7-8 January 1901, it wasn’t till late 1910 that a plan for an Australian Aviation Corps was submitted to the Military Board. Final approval to establish the Australian Flying Corps was promulgated in Military Order No.570 on 22 October 1912, with orders placed for two B.E.2a, two Deperdussin and a Bristol Boxkite to equip the new air arm.
Two pilots, Henry Petre and Eric Harison, and four mechanics - R.H Chester, G.A Fonteneau, C.V. Heath and A.E. Shorland were appointed to create a flying school. 734 acres of grazing land was purchased at Point Cook, Victoria at a cost of over £6,000 ($12,000), and the creation of the Central Flying School was announced on 7 March 1913. The first flying training course commenced on 17 August 1914. The four candidates on the course were Lieutenant R. Williams, Captain T.W. White, Lieutenant G.P. Merz and Lieutenant D.P. Manwell.
On 8 February 1915 the Government of India sought the assistance of the Australian Government to supply trained airmen, aircraft and transport for service in Mesopotamia (Iraq). The Australian Government replied that men and transport would be provided, but aircraft they could not. The unit (known as the Mesopotamian Half-Flight) was under the command of Petre and comprised White, Merz and Lieutenant W.H. Treloar and 41 other ranks. The Mesopotanian campaign culminated in the tragic siege of Kut and the subsequent ignominious surrender of the garrison included nine mechanics of the First Half-Flight.
Four Australian Flying Corps (AFC) squadrons also joined the British during World War I. No 1 Squadron flew against the Turks and Germans in the Middle East, while Squadrons 2, 3 and 4 served on the Western Front between September 1917 and November 1918. A variety of aircraft were flown, including Sopwith Camels and Snipes, RE8s, SE5 and DH5s. The Australian airmen engaged in photographic reconnaissance, artillery spotting and strafing and bombing raids on enemy troops and positions, and German aircraft. Additional Australian units were based in the United Kingdom. Nos 5, 6, 7 and 8 Squadrons were established to train aircrew for service in the four front line squadrons of the AFC.
The only Victoria Cross (VC) awarded to an AFC member was to Lieutenant F.H. McNamara of 1SQN for his heroism on 20 March 1917. However, the leading scorer of the AFC was 24 year old Captain A.H. Cobby from No 4 Squadron, who was credited with 29 aerial victories and awarded the Distinguished Flying Cross [DFC] (with two bars) and a Mention in Dispatches (MID).
During World War I Australian airmen also served with distinction with Royal Flying Corps/Royal Naval Air Service and Royal Air Force Units in Europe and the Middle East. Richard Williams commanded a Royal Air Force Wing and S.J. Goble flew operationally with the Royal Naval Air Service and commanded a squadron in France. When the Royal Australian Air Force was established on 31 March 1921, these men played prominent roles, Williams reaching the rank of Air Marshal and Goble the rank of Air Vice-Marshal.
But it was not only the new Service which was to benefit from the experience of World War I. Many of the pioneers of civil aviation (Charles Kingsford-Smith, Ross and Keith Smith and Hudson Fysh for example) gained their basic flying experience in the skies over France and the Middle East. Between 16 November-12 December 1919 Captain Henry Wrigley and Sergeant Arthur Murphy flew a BE2E from Point Cook to Darwin to meet Ross and Keith Smith. This was the first transcontinental flight.
http://www.raaf.gov.au/raafzone/html/history/wwI.html