Bostock had control of the USAAF Fifth and Thirteenth Air Forces, as well as No. 1 TAF, during Operation Oboe One, the invasion of Tarakan, commencing 1 May 1945. By this time RAAF Command comprised some 17,000 personnel. On Operation Oboe Six, the invasion of Labuan–Brunei in June, Bostock also had at his disposal aircraft based in Australia under Western and North-Western Area Commands. For Operation Oboe Two, the invasion of Balikpapan in July, Bostock marshalled forty Allied squadrons. His aim, in concert with that of Kenney and I Corps commander Lieutenant General Leslie Morshead, was to deliver the heaviest aerial bombardment possible against enemy targets, to enable Australian assault forces to land with minimal casualties. Together with a naval barrage, this resulted in a "scene of indescribable ruin" on the battlefield, and allowed seventeen waves of troops to disembark their landing craft without loss. MacArthur called the Labuan air offensive "flawless", while General Sir Thomas Blamey, Commander-in-Chief of the Australian Military Forces, congratulated Bostock on his "high order of control" and "ready and full cooperation" throughout the Borneo campaign.