In case you weren't aware, the US also pursued nuclear powered airplanes[1] with actual test units built. They're still sitting out there in Idaho a few miles off the highway and you can visit certain times of the year. Reading the placards (or the wiki) honestly scares me a bit, despite my thought that nuclear power makes a lot of sense for our energy needs. I don't love the idea of 500mph reactors up above me, even with modern airplane safety records.

[1] https://en.wikipedia.org/wiki/Aircraft_Nuclear_Propulsion