To what degree did the American and Australian tactical air offensive contribute to the Japanese defeat in the mountain campaign in the Owen Stanley Range? At the time Allied propaganda claimed that air attacks killed and wounded many Japanese and crippled their supply line, and this claim has been unquestioningly adopted by the Kokoda myth. If it was so, then it might be considered an important factor in any explanation of the outcome of the campaign. On the face of it this does not appear likely, as both the Allied ground support and air interdiction effort was feeble in terms of tonnage of bombs dropped. Moreover, the Allied Air Force (AAF) was dropping most of its bombs on Japanese shipping (which it usually failed to hit), not in an interdiction role along the Japanese supply line in Papua nor in a battlefield support role – now known as close air support. The result of the anti-shipping attacks on the Rabaul-to-Giruwa route was that two Japanese ships were sunk and two damaged, but 90 per cent of Japanese supplies got through to Papua up to the end of the Kokoda campaign in mid-November 1942. On land the Japanese were more concerned about the effect of heavy rain on their supply line than any problem caused by air attack, and far more bridges along the Giruwa-to-Kokoda supply line were destroyed by flood than by bombs.

The AAF was formed from all United States Army Air Force (USAAF), Royal Australian Air Force (RAAF) and Royal Netherlands East Indies Army Air Force units in Australia on 20 April 1942. Its north-eastern command exercised operational control in north Queensland and eastern New Guinea. Here ‘AAF’ is used to denote both it and the US Fifth Air Force, which was formed on 3 September 1942. General Kenney retained command of both organisations, and until the Nankai Shitai landing in Papua the major effort of the AAF was directed towards distant targets. Briefly, in late July, the attack was redirected against the ships of Yokoyama’s advanced force, then the heavy bombers switched their effort to supporting the Guadalcanal campaign by bombing Rabaul, Buka, Buin, the Shortland Islands and shipping to the west of the Solomon Islands.