This is similar to flying in air. I suppose when your craft is big (or long) enough you could leverage differences in luminous flux (or intensity?) to generate

This is similar to flying in air. I suppose when your craft is big (or long) enough you could leverage differences in luminous flux (or intensity?) to generate some thrust. The differences will be tiny and the necessary craft size big. One would have to run the actual numbers, but it _could_ work in principle. Compressing air by moving through it to leverage the resulting difference in velocities sadly won't work =( The steady state is then just the speed of air. I guess for light this also applies in a similar way.