Leader in 1944, Arjan Singh led the squadron against the Japanese during the Arakan Campaign. flying close support during the crucial Imphal Campaign and later assisting the advance of the allied forces to Rangoon, Burma. For his role in successfully leading� the squadron in combat, Arjan Singh received the Distinguished Flying Cross (DFC) in 1944. He was given command of the IAF Display flight flying Hawker Hurricanes after the war which toured India giving demonstrations. On 15 August 1947, he had the unique honour of leading the fly-past of over a hundred IAF aircraft over Delhi, over the red fort.
Promoted to Wing Commander, he attended Staff College at UK, and immediately after Indian independence became the AOC, Ambala in the rank of Group Captain. In 1949, promoted to Air Commodore, Arjan Singh took over the Air Officer Commanding of Operational Command, which later came to be known as Western Air Command. Arjan Singh had the distinction of having the longest tenure as the AOC of Operational Command, from 1949-1952 and again from 1957-1961. Promoted to Air Vice Marshal, he was the AOC-in-C of Operational Command. Towards the end of the 1962 war, he was appointed the DCAS and became the VCAS by 1963. He was the overall commander of the joint air training exercises "Shiksha" held between the IAF, RAF and RAAF.
On 01 August 1964, Arjan Singh took over as the Chief of Air Staff in the rank of Air Marshal, which became the pinnacle of this career. Arjan Singh was the first Air Chief who kept his flying category till his CAS rank. Having flown over 60 different types of aircraft from Pre-WW-2 era biplanes to the more contemporary, Gnats & Vampires, he also had flown in transports like the Super Constellation.
Arjan Singh's, testing time came in September 1965, when the subcontinent was plunged into war. When Pakistan launched its Operation Grand Slam, in which an armoured thrust targeted the vital town of Akhnur, he was summoned into the Defence Minister's office with a request for air support.
With a characteristic non-chalance, he replied "...in an hour." And true enough, the air force struck the Pakistani offensive in an hour.� He led the air Force through the war showing successful leadership and effort.
Though at a certain level, mistakes were made and planning could have been better, in all fairness, it must be said that the credit for thwarting Ayub Khan's grandiose plans to capture Kashmir is shared by the Indian Army and the Indian Air Force, and Arjan Singh for leading the air force through the war.
Arjan Singh was awarded the Padma Vibhushan for his leadership� of the air force, and subsequently in recognition of the air force's contribution in the war, the rank of the CAS was upgraded to that of Air Chief Marshal and Arjan Singh became the first Air Chief Marshal of the Indian Air Force. He retired in August 1969, thereupon accepting ambassador ship to Switzerland. He remained a flyer to the end of his tenure in the IAF, visiting forward squadrons & units and flying with them. Arjan Singh was a source of inspiration to a generation of Indians and Officers.
In recognition of his services, the Government of India conferred the rank of the Marshal of the Air Force onto Arjan Singh in January 2002 making him the first and the only 'Five Star' rank officer with the Indian Air Force.