doing so." From having few front line aircraft in 1939, the RAAF had become the fourth largest allied Air force by 1945. A number of aircraft were built under licence in Australia before the war's end, notably the Beaufort and Beaufighter, although the majority of aircraft were from Britain and later, the US. The Boomerang fighter, designed and built in four months of 1942, emphasised the desperate state Australia found itself in as the Japanese advanced. Australia also created, virtually from nothing, a significant female workforce engaged in direct war production. Between 1939 and 1944 the number of women working in factories rose from 171,000 to 286,000. Dame Enid Lyons, widow of former Prime Minister Joseph Lyons, became the first woman elected to the House of Representatives in 1943, joining the Robert Menzies' new centre-right Liberal Party of Australia, formed in 1945. At the same election, Dorothy Tangney became the first woman elected to the Senate. Post-war boom Menzies and Liberal dominance: 1949–72 Politically, Robert Menzies and the Liberal Party of Australia dominated much of the immediate post war era, defeating the Labor government of Ben Chifley in 1949, in part because of a Labor proposal to nationalise banks and following a crippling coal strike led by the Australian Communist Party. Menzies became the country's longest-serving Prime Minister and the Liberal party, in coalition with the rural based Country Party, won every federal election until 1972. As in the United States in the early 1950s, allegations of communist influence in society saw tensions emerge in politics. Refugees from Soviet dominated Eastern Europe immigrated to Australia, while to Australia's north, Mao Zedong's Chinese Communist Party won the Chinese Civil War in 1949 and in June 1950, Communist North Korea invaded South Korea. The Menzies government responded to a United States led United Nations Security Council request for military aid for South Korea and diverted forces from occupied Japan to begin Australia's involvement in the Korean War. After fighting to a bitter standstill, the UN and North Korea signed a ceasefire agreement in July 1953. Australian forces had participated in such major battles as Kapyong and Maryang San. 17,000 Australians had served and casualties amounted to more than 1,500, of whom 339 were killed. During the course of the Korean War, the Liberal Government attempted to ban the Communist Party of Australia, first by legislation in 1950 and later by referendum, in