McNamara was promoted to air marshal and became Chief of the Air Staff (CAS) in March 1979. He succeeded Air Marshal Sir James Rowland, who had been the first CAS to personally command the RAAF in a legal sense, following the abolition of the Australian Air Board in 1976. Previously, the CAS position was more akin to a chairman, "first among equals" with the other members of the Air Board. Under this earlier arrangement, McNamara considered that some senior commanders tended to behave like "regional war lords" who thought that the CAS existed purely to handle politicians and paperwork, while they (the commanders) got on with the Air Force's "real work". As CAS, McNamara put in train development of new strategies for the air defence of Australia, later remarking that "capability must be matched by ideas". He also supervised the selection process that chose the F/A-18 Hornet to the replace the RAAF's Mirage III fighters. McNamara personally favoured the F/A-18 due to its multi-role capability. Appointed a Knight Commander of the Order of the British Empire (KBE) on 31 December 1980, he was the last CAS to be knighted before Australia abandoned the imperial honours system.