I don't think you need to go to bombers to find good seats. Or even airplanes at all, though I've heard that airliners do tend to have pretty good seats for the pilots. Just start with buses and long haul trucks.
Though honestly, I think it's actually a solved problem. I just buy aftermarket Recaro seats. They know what they're doing.
I've seen bus- and truck drivers sit down and watched their seat just sink down a few inches, thinking that those must be so comfortable and absorb so much of the stuff that the passengers who sit on a bit of cloth stretched over vandalism-proof plastic chairs have to endure.
Though honestly, I think it's actually a solved problem. I just buy aftermarket Recaro seats. They know what they're doing.