Caleb James DeLisle (nprofile…8cpz)
A micro helium reactor might do the trick. And it might be possible to use tiny amounts of graphite encased uranium, just enough to power the plane for a few flights. The reactor could be shielded using specialized plastics, and boron. Then there is never enough nuclear fuel in the plane to cause a major nuclear accident. Just drop a few pellets into the reactor and off you go!