Nobody needs anything over a 1-5mW l@ser, unless for a professional reason.
Nobody needs a pilot's license, unless for a professional reason. Be careful what you wish for.
The solution is not to restrict the sale of lasers, since they have many legitimate uses. The solution is to make the penalty for aiming lasers at aircraft so severe and so guaranteed that people will refrain from doing it. A six-month suspended sentence won't suffice. A two-year or five-year prison sentence without parole would work pretty well.
Licensing of lasers that are dangerously powerful also makes sense, as long as this is not used as an excuse to artificially restrict their availability.
The American philosophy in many ways is to allow everything, except that which is forbidden. The European philosophy is increasingly to forbid everything, except that which is allowed.
Anyway, make the penalties severe enough, and actively track down and prosecute the perpetrators, and the laser incidents will go away. There are lots of guns in the world, but people don't fire guns at cars on the highway because they know they will go to jail for a long time for doing so. If they also know that they will go to jail for a long time for aiming lasers at airplanes, they'll stop doing it.
Some people can be stopped just by educating them, but the stupid ones have to be put in fear of prison in order to get them to behave.
For what it's worth, I notice a lot of people doing stupid things with high-powered lasers, besides pointing them at airplanes. Even the ones who claim to know what they are doing obviously don't know what they are doing when you hear them describe some of their "harmless experiments."
And for those who care nothing about laws or the safety of others, do keep in mind that if you aim that powerful laser in the wrong direction, it will bounce off a specular surface and put a nice permanent burn mark on your retina, just as it will with anyone else.