I believe the set designer of Dr. Strangelove had a newspaper photo of a B-52 instrument panel (and possibly the Monogram B-52 kit?) to go from, but that was it.
Fail Safe was in the same position with a smaller budget (so no miniatures), and they were supposedly stonewalled on every effort to get bomber film; they eventually scrounged up about 800 feet of mostly B-58 stock footage. Some of it was printed as negative to pass for night shots.
Movie stills:


Positives:

Fail-Safe's bomber interior shots were supposedly filmed in the cockpit of an actual airplane (what type I don't know) in a hangar in Long Island.
Ironically, another movie was being shot in a converted hangar in Long Island about the same time, and had no trouble getting a lot of military stock footage... It was titled
Santa Claus Conquers the Martians.

_________________

All right, Mister Dorfmann, start pullin'!
Pilot: "Flap switch works hard in down position."
Mechanic: "Flap switch checked OK. Pilot needs more P.T." - Flight report, TB-17G 42-102875 (Hobbs AAF)