[justin66]

Yeah. Two crewmen, something like twice as much payload weight (originally designed to carry a nuclear bomb or two instead of a top-tier reconnaissance package), and apparently less ceremony in general than the U-2. The U-2 really wants to have a chase car (!) when landing to call out what the pilot cannot see, from the sound of things the WB-57 doesn't do that. (okay, some irony there considering recent events...)

[ianburrell]

I was thinking about what could replace WB-57. Large private jets (Gulfstream G650) can get up to 51k ft, and maybe could be modified to go higher. Global Hawk drone can go up to 60k ft, and the Air Force is retiring them.