" The U-2 can still fly higher than the Global Hawk, carry a greater payload, and its sensors have more of a slant range. The Global Hawk also lacks de-icing equipment and countermeasures against Russian SAMs. We may be entering the age of drones, but old-fashioned piloted planes can still do a thing or two." Why not just copy the U2 and make an improved, unmanned version?
[1] https://www.amazon.com/Boyd-Fighter-Pilot-Who-Changed/dp/031...