Leonard Monk Isitt was born on 27 July 1891 at Christchurch, New Zealand, the elder son of Leonard Monk Isitt and his wife, Agnes Martha Caverhill. His father was a Methodist minister, temperance leader and politician. Leonard was educated at Mostyn House School, Cheshire, England, and at Christchurch Boys’ High School. On leaving school he took up farming as a cadet and served in the territorial forces before enlisting in the New Zealand Expeditionary Force in April 1915.
Isitt served with the New Zealand Rifle Brigade in Egypt and France and was wounded at the battle of the Somme in September 1916. After convalescing in England he transferred to the Royal Flying Corps and trained as a pilot; he then served on army co-operation and in bomber squadrons in France. Following the armistice he completed specialist training with the Royal Air Force. He returned to New Zealand in October 1919 and took up a position with the fledgeling air service of the New Zealand military forces based at Sockburn, where he was responsible for aircraft and equipment, the supervision of refresher training for ex-First World War aviators, and liaison with the Canterbury Aviation Company.
On 26 April 1920 Leonard Isitt married Elsie Gladys Caverhill at Wellington; they were to have two daughters. Of strong mind and lively personality, Elsie was a pillar of support throughout her husband’s varied career. She was active on a number of committees during the Second World War.
Training for the New Zealand Air Force (Territorial), army co-operation work and the administration of aviation activities throughout New Zealand featured in Isitt’s duties until June 1926, when he was seconded to the RAF in England. There he completed courses in flying instruction, air photography, naval co-operation and parachute servicing, and attended the School of Army Co-operation. He also acted as New Zealand liaison officer to the Air Ministry and was attached to the New Zealand prime minister’s party at the 1926 Imperial Conference in London. He returned to New Zealand in February 1928 via Canada, where he was attached to the Royal Canadian Air Force for several weeks to further his experience, and was appointed to command the new air base at Hobsonville. During the following eight years, Isitt was occupied in developing Hobsonville as a land aerodrome and flying-boat base and in providing a range of military and general air services in the Auckland region and elsewhere.
As the international situation worsened during the 1930s Isitt became increasingly concerned for New Zealand’s defence and saw the need for an air link to North America. In political and commercial circles he quietly but persistently promoted the case for establishing a civil air route across the Pacific, which could be turned to military purposes in the event of war.
When the Royal New Zealand Air Force was established as a separate service on 1 April 1937, Isitt was promoted to wing commander, then group captain. As air member for personnel, he held a key appointment in the time of rapid expansion through to the opening stages of the Second World War. For his contribution to the remarkable achievements of this period he was made a CBE. In March 1940 he went to Canada as the New Zealand representative on the supervisory board of the Empire air training scheme, from where he also represented New Zealand on the British Purchasing Commission and British Supply Council in North America.
When formal diplomatic relations were established with the United States, Isitt was appointed to the staff of the New Zealand minister in Washington in January 1942; he represented New Zealand on a wide range of military, training and supply matters in the United States, Canada and Britain. In May 1942 he was promoted to air commodore and posted to London, where he established the RNZAF Overseas Headquarters. He oversaw New Zealand’s extensive and growing contribution to the air war in Europe and to RAF activities worldwide.
Isitt left Britain in December 1942 and returned to take up duties in the Air Department, Wellington. He became deputy chief of air staff in March 1943 and was appointed chief of air staff with the rank of air vice marshal on 19 July 1943 – the first New Zealander to fill that office. He was singularly well qualified for the responsibilities of his new post, to which he also brought the advantages of established political relationships and allied military connections.
Isitt used his associations and considerable diplomatic skills to good effect in securing an active role for the RNZAF in the south Pacific for the remainder of the war, and thus helped to maintain a profile for New Zealand’s interest in the region. It was appropriate that he should be chosen to be New Zealand’s signatory to the Japanese surrender in Tokyo Bay on 2 September 1945. His contribution to the Allied war effort was recognised by the United States in October 1945 when he was made an officer of the US Legion of Merit, and his services to New Zealand were recognised when he was made a KBE in January 1946.
Sir Leonard Isitt retired as chief of air staff in May 1946 and was appointed chairman of the board of the New Zealand National Airways Corporation (NAC). He was also appointed a director of Tasman Empire Airways Limited (TEAL), of which he became chairman in 1947, and the New Zealand director of British Commonwealth Pacific Airways until it was wound up in 1954. He remained chairman of both NAC and TEAL until March 1963, and thus presided over the development of New Zealand’s post-war domestic and international airline interests. He travelled widely, often accompanied by Lady Isitt, to follow aviation industry developments, to attend board meetings and conferences, and as a member of the executive committee of the International Air Transport Association. On his retirement as chairman of NAC and TEAL he became chairman of Standard–Triumph New Zealand, Motor Assemblies Limited and Leyland Motors of New Zealand until his final retirement in 1966.
Leonard Isitt was a man of personal charm and quiet friendly dignity. He was a keen angler and applied his love of gardening to his home in Paraparaumu. He died at Lower Hutt on 21 January 1976; his wife had died in 1970. He was accorded a funeral with full military honours in Wellington.