The problem with these very powerful lasers is that they are potentially quite dangerous. They are also illegal to use for signaling aircraft. Illegal as in a Federal felony with penalties of potentially 5 years in jail and/or a $150,000 fine! You may have read about various prosecutions in the news of late. While they might make an exception in an actual survival situation, I wouldn't want to bet on it. And, soem pilots are finding it worthwhile to claim eye injury, adding to the potential liability.

Greatland Laser has developed a Green Laser Flare that they have been selling to the military and which will be introduced for civilian use at SHOT Show next week. In my tests we exceeded 30 miles range. Because this is a Class IIIa (3R) "Laser Signaling Device intended for use as an emergency distress signal," it will be legal for use as a distress signal and there is currently a bill before Congress (already passed the House) that will explicitly enable such use so there is no question.

So, the concept is fine, but I'm going to stick with legal lasers for survival use. Note that the green lasers are fine for terrestrial use, but for marine use probably want to stick with red as the green doesn't work very well with the night vision goggles commonly used by the Coast Guard for night SAR.