Extremely able and practical, Synnot came to be regarded as one of the country's most outstanding defence force chiefs. A strong believer in deterrence and an advocate of close co-operation with America and countries in the Pacific region, Synnot emphasised the need for a strong military capability for national defence and for joint operations with Australia's allies overseas. He was said to have done more to equip Australia's armed forces with up-to-date military technology than any of his predecessors. In particular, he was instrumental in persuading the Australian government of the need to upgrade the country's air force with the acquisition of the F/A-18 Hornet.