My dad flew in B-36s and B-47s when he was in SAC. This was when the US always had nuclear equipped bombers in the air at all times. Long after he retired, he told me they had orders to bomb Leningrad if they got the green light.
I was friends with a guy, now deceased who flew B-36s alone with just about everything else from 1944-1968.
After he retired, he worked as an instructor at Ft. Rucker. They asked if he was qualified for twin engines, he replied that he was qualified for 10.
He said that in the early days, only 3 bases, one of them Eglin could handle the B-36 because it took a very long runway to take off.