Humphrey became Officer Commanding RAF Akrotiri in February 1959 and then attended the Imperial Defence College in 1962 before being promoted to air commodore on 1 July 1962. He became Director of Joint Plans at the Air Ministry in November 1962 and then Director of Defence Plans (Air) at the Ministry of Defence in April 1964 Promoted to air vice marshal on 1 January 1965, he became Air Officer Commanding Air Forces Middle East on 15 December 1965 and, following the withdrawal from Aden in November 1967, he was mentioned in despatches for his services in operations there on 23 January 1968. He went on to be Air Member for Personnel with the acting rank of air marshal on 18 March 1968 and advanced to Knight Commander of the Order of the Bath in the 1968 Birthday Honours.