The advent of cheap, powerful hand-held lasers has become a real problem for aviation, with daily reports of pranksters (or, according to various headlines, "thugs," "idiots" and "laser losers") shining laser penlights into cockpits and temporarily blinding pilots. The number of incidents is on the rise, with 148 such attacks reported in the U.S. in just the first two months of 2009, according to the FAA—an average of 2.7 incidents a day. For some reason, there have been more attacks in the Western states: San Jose, California, has had a particular problem.
Worried that handheld lasers will be banned (they already have been in the Australian state of New South Wales, and there's talk of it in Ireland), the International Laser Display Association, which represents the laser show industry, has set up a website about laser pointer safety. This FAA Powerpoint presentation, from a conference in March, gives a good overview of the problem.