Along with Henry Petre, he established Australia's first air base at Point Cook, Victoria, and its inaugural training unit, the Central Flying School (CFS), before making his historic flight in March 1914.

Following the outbreak of World War I, when Petre went on active service with the Mesopotamian Half Flight, Harrison took charge of instructing student pilots of the Australian Flying Corps at CFS, and maintaining its fleet of obsolescent aircraft.

Harrison's technical abilities and association with military flying from its earliest days in Australia earned him the title of "Father of the RAAF" for many years, until the mantle was assumed by Air Marshal Sir Richard Williams.

[2][3] Gaining employment as an instructor for Bristol, he taught flying on behalf of the company in Spain and Italy, as well as in Halberstadt, Germany, where he became aware first-hand of that country's militarism; some of the students he trained and examined later served as pilots in the Luftstreitkräfte during World War I.

The English-born Henry Petre, a former solicitor employed by Handley Page, and Harry Busteed, an Australian who was Bristol's chief test pilot, successfully applied.

The wind, along with the aeroplane's low power and the weight of its passengers, almost led to the Boxkite crashing on take-off and prevented it gaining more than 30 feet (9 m) in altitude before Harrison terminated the flight.

[11] Petre crashed a Deperdussin on 9 March and a concerned Minister for Defence, Edward Millen, made a surprise visit to Point Cook two days later to inspect the wreckage.

[15][16] With little in the way of enemy resistance the aircraft were never assembled in New Guinea and Harrison had to return in January 1915 without leading the first Australian airmen into combat, a distinction that instead went to Petre as commander of the Mesopotamian Half Flight later that year.

Many of his students went on to play a prominent role in the future Royal Australian Air Force (RAAF), including Bill Anderson, Harry Cobby, Adrian Cole, Frank McNamara, Lawrence Wackett, and Henry Wrigley.

[21][23] Harrison began a long association with engineering and air safety when he was posted to Britain for secondment to the Aeronautical Inspection Directorate towards the end of World War I, departing Australia on 22 October 1918 and returning on 9 January 1920.

[2][24] He transferred as a flight lieutenant (honorary squadron leader) to the newly formed Australian Air Force on 31 March 1921, becoming one of its twenty-one founding officers; the adjective "Royal" was added to the service's name in August that year.

A reorganisation of the directorate along public service lines in 1940 permitted qualified civilian engineers to be recruited for work that required increasing technical expertise, without them having to join the Air Force.

[1][2] The Minister for Air, Arthur Drakeford, commented that "all members of the service, and, indeed, all Australians interested in aviation, must feel his loss as the snapping of one of the last links with the pioneer days of flying".

[46] Despite his accomplishments in overseeing the training of every student pilot who served in the Australian Flying Corps during World War I, Harrison received no decorations or other official recognition, prompting Group Captain Mark Lax, at the 1999 RAAF History Conference, to describe him as "perhaps the unluckiest of the entire AFC ... an unsung hero".

[47] Lax added that, as an instructor, Harrison's "caring, personal approach resulted in a fatality free run with high percentage graduation – surely a remarkable achievement for the time".

[5][6] His technical expertise, long association with Australian military aviation as a founder member of the AFC and the RAAF, and stronger personality tended to overshadow the part played by Henry Petre, whom historian Douglas Gillison considered "equally entitled" to such an accolade.

[5] Reviewing the contributions of Petre and Harrison in his volume of The Australian Centenary History of Defence in 2001, Alan Stephens concluded that "perhaps any judgement would not only be moot but also gratuitous, as by circumstance and achievement both men properly belong in the pantheon of the RAAF".