Australian Flying Corps, in January 1920. On 17 June, accompanied by Captain Hippolyte De La Rue, he flew a DH.9 to a height of , setting an Australian altitude record that stood for more than ten years. He transferred to the Royal Australian Air Force as a flight lieutenant in March 1921, becoming one of its original twenty-one officers. On 30 November, he married his cousin Katherine Cole in St Peter's Chapel at Melbourne Grammar School; the couple had two sons and two daughters. Squadron Leader Cole was posted to England in 1923–24 to attend RAF Staff College, Andover, returning to Australia in 1925 to become Director of Personnel and Training. Promoted to wing commander, he was in charge of No. 1 Flying Training School (No. 1 FTS) at RAAF Station Point Cook, Victoria, from 1926 to 1929. The first Citizens Air Force (reserve) pilots' course took place during Cole's tenure at No. 1 FTS; although twenty-four accidents occurred, injuries were minor, leading him to remark at the graduation ceremony that the students were either made of India rubber or had learned how to crash "moderately safely". Cole held command of RAAF Station Laverton from 1929 until his appointment as Air Member for Supply (AMS) in January 1933. The AMS occupied a seat on the Air Board, which was chaired by the Chief of the Air Staff and was collectively responsible for control and administration of the RAAF. In March 1932, Cole accepted an invitation from the Lord Mayor of Melbourne to serve as Deputy Chairman of the 1934 MacRobertson Air Race from England to Australia, to celebrate Melbourne's Centenary. Provision of the RAAF's radio facilities and technicians was considered a boon for contestants, though Cole later recorded that his role involved "twenty months' hard work, without pay ... with loads of scurrilous and other criticism". Promoted to group captain in January 1935, he became the inaugural commanding officer (CO) of Headquarters RAAF Station Richmond, New South Wales, on 20 April 1936. The new headquarters, which had been formed from elements of two of the base's lodger units, No. 3 Squadron and No. 2 Aircraft Depot, supplanted an earlier arrangement where the CO of No. 3 Squadron had doubled as the station commander. Cole was appointed a Commander of the Order of the British Empire in the Coronation Honours of 11 May 1937, and attended the Imperial Defence College in