China and Russia bragged about their hypersonic missiles,
well lasers move at the speed of light, checkmate.
Depends on the solution for atmospheric jitter. Taking a shot at long range is problematic, as dispersion and diversion of the beam occurs. Best to fire a laser defense from a high altitude position or from a space location.
The target image is roiled by refraction, reflection—obscured by dust, aerosols, clouds. The firing solution is where the target is in most probability located at a predicted moment of intercept.
Can you slew the barrel of the laser fast enough to keep up with the relative angular change of the incoming projectile? Can you do it well enough that the total energy delivered by the laser will (say) roughen or penetrate the airframe, at which point the friction of the projectile at hypervelocity will finish the job for you? (or at least maybe screw up the CEP if you have a tungsten penetrator)
Windmills and solar panels will not be enough to power these rigs 24x7.
What to do....