The British Commonwealth Air Training Plan (BCATP), often referred to as simply "The Plan", was a massive, joint military aircrew training program created by the United Kingdom, Canada, Australia and New Zealand, during the Second World War. BCATP remains as one of the single largest aviation training programs in history and was responsible for training nearly half the pilots, navigators, bomb aimers, air gunners, wireless operators and flight engineers who served with the Royal Air Force (RAF), Royal Navy Fleet Air Arm (FAA), Royal Australian Air Force (RAAF), Royal Canadian Air Force (RCAF) and Royal New Zealand Air Force (RNZAF) during the war.