Complex sentence: He served with the Royal Air Force from 1929 to 1932, then worked in civil aviation until the outbreak of the Second World War, during which he again served with the RAF, becoming Commander of RAF Winkleigh on 29 March 1944.
Split into simpler sentences: He served with the Royal Air Force from 1929 to 1932, then worked in civil aviation until the outbreak of the Second World War. During the Second World War he again served with the RAF, becoming Commander of RAF Winkleigh on 29 March 1944.