Hardman was promoted to acting
air vice-marshal on 1 October 1945. He remained in South-East Asia following the cessation of hostilities, taking over as Air Officer in Charge of Administration for ACSEA (later Air Command Far East) in January 1946. Hardman's wartime rank of air commodore became substantive on 1 October 1946, and this was followed by substantive promotion to air vice-marshal on 1 July 1948. He was raised to acting
air marshal on 1 October 1951. On 14 January 1952, Hardman was appointed
Chief of the Air Staff (CAS) of the
Royal Australian Air Force (RAAF), succeeding Air Marshal
George Jones, who had served ten years in the position. The decision by Australia's
Prime Minister,
Robert Menzies, to appoint an RAF officer caused resentment in the RAAF. This was compounded when Menzies stated his reason as being that there was "no RAAF officer of sufficient age, or operational experience, to take the post of Chief of the Air Staff", which appeared to ignore the wartime records of such figures as
John McCauley and
Frederick Scherger.
The Daily Mirror in
Sydney was one of several media outlets to voice a "stern protest" over the matter. Menzies also felt he could justify the appointment of an outsider on the grounds that the RAAF's
geographically based command-and-control system needed reorganisation along functional lines, a system with which a senior RAF member would be familiar. Britain's CAS, Marshal of the Royal Air Force
Sir John Slessor, was, somewhat reluctantly, responsible for fulfilling the Australian Government's request for a suitable officer. In putting forward Hardman as the "outstanding candidate" for the Australian post, Slessor tried to avoid what he called "the follies of some years ago", referring to Air Chief Marshal
Sir Charles Burnett's controversial tenure as CAS on secondment from the RAF early in World War II. Hardman made two major changes to the structure of the Air Force to streamline command and control: integrating RAAF Headquarters,
Melbourne, with the
Department of Air, and supplanting the geographical area commands with three functional organisations, namely
Home (operational),
Training, and
Maintenance Commands. The functional command system has been described by historian Alan Stephens as Hardman's "major legacy to the RAAF". He also formed a policy agreement with the
Chief of the Naval Staff, Vice Admiral
Sir John Collins, covering joint responsibility and cooperation for maritime warfare. During Hardman's term as CAS,
No. 78 (Fighter) Wing was re-equipped with RAF
de Havilland Vampire jet fighters to garrison Malta and support British operations in the Mediterranean. He was appointed a
Knight Commander of the Order of the Bath in the
Queen's Birthday Honours promulgated on 5 June 1952, and raised to substantive air marshal on 1 July. (centre), and
Lord Mountbatten (right) at a ceremonial parade for No. 78 Wing RAAF on its departure from garrison duty in Malta, December 1954|alt=Three men in dark military uniforms with peaked caps As a protege of Slessor, Hardman proclaimed: "An air force without bombers isn't an air force." He maintained that the only way to attain "true and enduring air superiority" was by attacking the enemy's vital centres, which included its means of producing fighters. He recommended that the RAAF purchase one of Britain's
nuclear-capable "
V bombers"—the
Vickers Valiant,
Handley Page Victor, or
Avro Vulcan—though this never eventuated, and Australia's jet bomber remained the
English Electric Canberra until the long-delayed introduction of the
General Dynamics F-111C in 1973. Towards the end of his tenure as CAS, Hardman gave an interview in which he criticised
Army and
Navy operations against a backdrop of continuing interservice rivalry for the defence budget. He was quoted as saying: "The Air Force in this country, for either defence or offence, is the only force worth while. It can be sent anywhere in the world to the point where it can do most good and be rapidly switched to any other point." In contrast to the initial disquiet at his appointment, upon his departure from Australia Hardman was described by
The Age as "the outstanding CAS in the RAAF's history", a "brilliant organiser", and a "master of the theory of air power". In December, he represented the Air Council at No. 78 Wing's farewell parade in Malta, reminding the personnel gathered that he had been present at the wing's march through Sydney in July 1952, prior to its departure for the Mediterranean. He was promoted to
air chief marshal on 1 April 1955. In July 1956, he presented a Squadron Standard to his old unit, No. 19 Squadron. That October, he presided over the inquiry into the
fatal crash of Vulcan XA897 at
Heathrow Airport after its maiden round-the-world flight, the only survivors of the six crew members being the pilot and Air Marshal
Sir Harry Broadhurst. Hardman was succeeded as Air Member for Supply and Organisation by Air Chief Marshal
Sir Walter Dawson on 1 January 1958, and was raised to
Knight Grand Cross of the Order of the British Empire the same day. He retired from the RAF on 29 January. ==Later life==