Re: How high?
I can easily hit the power lines 2+ miles from my house using a 500mW green laser pointer held in my hand.
I've never tried hitting a plane because I've mastered the whole actions/consequences thing, plus they are already at about 15,000' by the time they're over my house.
As others have pointed out, the atmospheric backscatter makes the beam easily visible. Which is why it works so well as a star pointer, the reason I bought it in the first place. (Although I suppose some Jovian pilot may have complained when I pointed out the planet to my wife the other night.)
Biting the hand that feeds IT
