Lasers in Airspace
There are many valid reasons that lasers are aimed into airspace. Lasers are used in industry and research, such as in atmospheric remote sensing, and as "guide stars" in adaptive optics astronomy. Lasers and searchlights are used in entertainment; for example, in outdoor shows such as the nightly IllumiNations show at Walt Disney World's Epcot. Laser pointers are used by the general public; sometimes they will be accidentally or deliberately aimed at or near aircraft. (Of course, no unauthorized person should deliberately aim any type of laser at or near an aircraft.)
Lasers are even used, or proposed for use, with aircraft. Pilots straying into unauthorized airspace over Washington, D.C. can be warned to turn back by shining eye-safe low-power red and green lasers at them. At least one system has been tested that would use lasers on final approach to help line up the pilot on the proper glideslope. NASA has tested a Helicopter Airborne Laser Positioning System. The FAA has tested laser-projected lines on airport runways, to increase visibility of "hold short" markings.
Because of these varied uses, it is not practical to ban lasers from airspace. This would unduly restrict legitimate uses, it would not prevent accidental illumination incidents, and it would not stop someone who deliberately, out of malice or ignorance, targeted aircraft. For this reason, practical laser/aviation safety is based on informed users and informed pilots.
Read more about this topic: Lasers And Aviation Safety