I've read about when there was always at least 1 B-52 in the air during the cold war. The logistics of that happening was insane and included in-air refueling.
Of course there were accidents. One of them crashed and released nuclear material in Spain at a site that's still being cleaned up decades later..
https://en.wikipedia.org/wiki/1966_Palomares_B-52_crash
I really hope we start putting those old planes up in the air again, sounds like a safe and sound plan.