When the Second World War began, Bullus was thirty-three years old. Too old for active service, in August 1940 he was commissioned as a pilot officer in the Royal Air Force (RAF) Volunteer Reserve. He served at the Air Ministry until 1943,[] when he was promoted to the rank of flight lieutenant and transferred to southeast Asia to join Lord Mountbatten's staff. eventually reaching the rank of wing commander, demobilised in December 1945.]