There would certainly have been scope for another 2 parts. Aside from the passing references to the USAF other noticeable bits that were either not mentioned or merely skipped over were the Hunters and Javelins the backbone of the UK Air Defence before the Lightning, the Sea Vixen, Buccaneer and Scimitar for maritime, the VC10! Then later Air Defence with the F4 and attack with Jaguar, Harrier, Buccaneer.
I suppose, looking in the round, the first part was the British leadership in jet engines and then it was concentrated on design with the attack and defence aspects of the Cold War with our nuclear deterrent and the associated air defence on the one hand and the Russian on the other.