[jasonwatkinspdx]

Yeah, the 1950s involved serious consideration of some truly horrific nuclear flight concepts, so I wouldn't be so dismissive of risk as a factor. Not like airliner crashes are awesome, but they don't drop a reactor core on whatever they crash into. Not to mention proliferation concerns, operator staffing requirements, security staffing requirements. There's very straightforward reasons nuclear powered flight on earth never went past the earliest exploration of a couple prototypes. Russia is working on a nuclear powered cruise missile and has already had one serious mishap with it.