The Battle of Port Moresby was an aerial battle fought between the Royal Australian Air Force (RAAF) and United States Army Air Force (USAAF) on one side and the Imperial Japanese Army and Imperial Japanese Navy on the other between 3 February 1942 and 17 August 1943 over Port Moresby, Papua. At the start, the defenders consisted only of Australian Army anti-aircraft batteries and machine-guns, but by late March had been strengthened by the arrival of Kittyhawk fighters from No. 75 Squadron RAAF. However, in just nine days they lost 11 aircraft and only the arrival of replacements enabled the unit to maintain ten serviceable machines.