In 1939, just after the outbreak of the Second World War, Australia joined the Empire Air Training Scheme, under which flight crews received basic training in Australia before travelling to Canada for advanced training. A total of 17 RAAF bomber, fighter, reconnaissance and other squadrons served initially in Britain and with the Desert Air Force located in North Africa and the Mediterranean. Thousands of Australians also served with other Commonwealth air forces in Europe during the Second World War. About nine percent of the personnel who served under British RAF commands in Europe and the Mediterranean were RAAF personnel.