Guam-SEA 488k TOGW 35K cruise altitude .86 machAll kinds of answers. They were built to overfly the USSR at 50k ft on the way to their targets. Then, radar SAMs were developed and they initially stayed high and used lots of ECM, Quail, and Hound Dog (later SRAM) to fight their way in. Then, spent a couple decades practicing to ingress at 500 agl, or less. Now, they are back up high for most recent wars and missions.
I think when they just need to cover distance (cross an ocean, etc) they typically go at about 35k ft. Someone with direct knowledge will pipe up, I'm sure.
The planes (and crews) are incredibly flexible, and that means they have needed to be at various altitudes.
My neighbor worked downstairs on the B-52 missions in SAC. My old flight instructor went in the AF in 1954 and spent most of his time until retirement in SAC flying the 52's.Only 43 missions
It was my turn in the barrel
I was an OV10 pilot 185 missions.
Got drafted by SAC