Boyle became Chief of the Air Staff and was promoted to air chief marshal on 1 January 1956, the first graduate of the RAF College Cranwell to be appointed to this post. In this role he deployed British air power during the Suez Crisis in October 1956 and defended the RAF against the views of Duncan Sandys, the Minister for Defence, who believed that the V bomber force rendered manned fighter aircraft redundant. He was advanced to Knight Grand Cross of the Order of the Bath in the 1957 New Year Honours and promoted to the rank of Marshal of the Royal Air Force on 1 January 1958 before retiring in January 1960. In retirement Boyle became Vice-Chairman of the British Aircraft Corporation. He was instrumental in founding the RAF Museum at Hendon and became the first Chairman of its trustees. He was also Vice-Chairman of the RAF Benevolent Fund for most of the 1970s and President of the Royal Air Force Club. He died at Sway in Hampshire on 5 May 1993. Boyle married Una Carey in 1931; they had two sons and a daughter.