Our note: That does not prove the earth is flat. The laser can be aimed up/down and left/right. Point it above the horizon line any way you want just to get the laser light seen at the target location.
Aimed and traveling over the horizon the laser beam is refracted by the atmosphere and subject to other thermal distortions, before its ever widening beam (laser beam divergence) makes it to the distant target.
This only proved that the laser was bright enough to be seen from those distances. Nothing else.
