Chapter Four explores proposals for the creation of a postwar United Nations air force in Britain and the United States during the Second World War. Aviation, the chapter shows, emerged as a central component of internationalist campaigns for the creation of a postwar international security organization. Allied aerial ascendancy appeared to offer the opportunity, and the aeroplane the perfect tool, for the creation of a new system of collective security and international governance. By examining discussions and proposals within internationalist organizations and state planning committees, the chapter examines the coalition of interests which formed in support of the force. In the United States, it was supported by proponents of international law and of a strong United Nations Organization, and by a lobby keen to see the expanded wartime aviation industry used for postwar peacekeeping. In Britain meanwhile support was built on visions of joint Anglo-American policing of the world, and hopes of British influence over an integrated postwar Europe. An international air force was incorporated into the blueprint for a United Nations Organization at the 1944 Dumbarton Oaks Conference, and although the force was never formed it remains a part of the United Nations Charter to this day.