No. 21 Squadron

Originally formed on 20 April 1936 at Laverton in Victoria, as a reserve unit of the Citizen Air Force, 21 Squadron flew wartime patrols escorting troopships across the Great Australian Bight enroute to Europe. After re-equipping with Wirraways, the unit moved to Singapore Island in August 1940. On arrival its aircraft were gradually replaced with Brewster Buffalo fighters and the unit then moved to north-east Malaya. The Japanese invasion one week later resulted in two aircraft being destroyed and five damaged on the ground. The remaining serviceable aircraft flew to Butterworth and withdrew first to Ipoh and then to Kuala Lumpur.

With only reserve aircraft available, the unit merged with 453 Squadron to become 21/453 Squadron on 24 December 1941. The new squadron then moved to Sumatra but Japanese advances once again forced a withdrawal. The unit eventually abandoned Java and sailed to Fremantle, where it was disbanded on 4 March 1942.

Reequipped with Vultee Vengeance dive-bombers in September 1943, the unit undertook advanced training at Lowood in Queensland from December. In early 1944 the squadron moved to Nadzab and commended operations against barge hide-outs (now of crucial importance to Japanese attempts to supply their troops in New Guinea) and joined in combined raids on airstrips in Hansea Bay, Alexishafen and Madang.

The short flying range of the Vultee Vengeance rendered it unsuitable for operations in New Guinea. 20 Squadron relocated to Camden to convert to Liberator heavy bombers in March 1943. Operations were not flown with these aircraft until January 1945, when unit aircraft attacked targets at Laga and Moena Island, an enemy convoy near Koepang, troop areas at Tawo, and fuel tanks on Tarakan and Borneo. During the final months of the Second World War, the unit bombed targets at Labuan and Balikpapan, in support of a landing assault.

21 Squadron conducted shipping escorts after the end of the war, before moving to Tocumwal in New South Wales in November 1945.