B-52: as much as I appreciate the other ones and love the B-58, when someone says Cold War strategic bomber, who does not mentally envision the BUFF?
F-4: do everything and do it everywhere Western fighter.
Mirage III/V family: classic Delta scene widely around the world.
F-104: love it or hate it, they were everywhere and a lynch pin in Western defense doctrine.
F-14/F-15: unbeaten champions of air-to-air that scared the Reds, and all but guaranteed that whatever Western aircraft were behind them would get through to the target unmolested by MiGs and Sukhois.
C-130: nothing else flies/flights if the trash does not get hauled.
C-141: where did these NOT show up?
Vulcan: wasn’t it Breshnev said the Vulcan V-bomber was what kept him up at night?
Hunter: the subsonic F4/Mirage of its day that was everywhere, and a serious problem for the bad guys.
Harrier: developed into something beyond a “novelty A-4” take you up there Reds one more headache to solve.
HONORABLE MENTIONS
Every other carrier based fighter and attack plane, without which there be no purpose to have the aircraft carriers.
F-100: the main plane for TAC until the F4 supplanted it. Practically everyone flew it and cut their teeth on it.
BAC Lightning: THE interceptor.
Century Series: as extraordinary as the series was, and while some of them could do one or two things a little better than the F-4, these aircraft were all purpose-built limited-mission aircraft that were eventually wrapped up and meld together into what the mighty F-4 Phantom was.
F-80/-84/-86/F9F/Jaguar/Super Mystier/SR-71/U-2/ everything else: some incomparables, some were superb and adaptable in what they did, some were jack of all trades. Many of the third and fourth generation aircraft were designed for the shoulders of those aircraft. But I believe that they were too specialized or not ubiquitous enough.