I may risk being too credible here, but a $80 drone is a lot more expendable than a $40m laser tank. The drone can be considered a consumable. Hell, mark the drones down as ammo.

Depending on how long you do it, how powerful the laser, and how quickly it can cool off at the same time.

And like the other guy said, you can make really good mirrors if you only care about one wavelength.

But the drone stays in the air by making wind, which would cool down the mirror?

not if you have total internal reflection