One exhibit I really think is missing from RAF post-war collections, is a proper PV5 Neptune MR.1, as used by Coastal Command, and I would really like to see one here.
Isn’t there one of these (ex-RAF in original config) in the States? There was a few years back.
If it’s an aircraft in ‘Foreign’ hands, I’d go for the XV-6A at the Smithsonian.
For a ‘Foreign’ aircraft, a Brewster Buffalo