Difficult to say. I love old warbirds from WWII. It would be too hard to pick between them. I have several favorites including the P-40 Warhawk, PBY Cataline, the Hurricane, the Supermarine Spitfire, P-51 Mustang, F-4U Corsair, P-38 Lightning, the De Havilland Mosquito, BF-109, ME-262, or the Japanese Zero.
As far as more modern aircraft go, I love the F-14 Tomcat, the F-8 Crusader, Mirage 2000, Eurofighter Typhoon, F-18 Hornet, Mig-29, SR-71 Blackbird, or SU-47 Berkut.
As for civilian aircraft, there's the Douglass DC-3 or the Lockheed Constellation. Not only are these planes gorgeous, but they represent an era when flying was actually fun and you could get on an airplane without having to get your privates groped by a big burly TSA agent.
Don't make me pick just one of these because I'll spend all day trying to figure out which one I like the most.
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