Yes, both USA and Soviet experimented with nuclear powered planes during the 60s. The problem was how to shield the pilots from radioactivity. https://en.wikipedia.org/wiki/Nuclear-powered_aircraft
They also experimented with nuclear powered drones. https://www.popularmechanics.com/military/research/a33565112...
And Russia now claims to have a nuclear engine that can make a cruise missile fly for days. https://en.wikipedia.org/wiki/9M730_Burevestnik