Some of this year's cheeriest holiday decorations look great, but use lasers or other focused light projected on the side of your home for a stunning display. But they can be dangerous if you accidentally have them aimed skywards, where they can blind pilots of low flying planes or helicopters, or be mistaken for laser strikes. If your holiday lights use these types of lights, they're pointing into the sky, and you live near an airport, the lasers can cause "flash blindness" for pilots flying in and out. As The Consumerist points out, they may also be mistaken as laser strikes and cause a false alarm for local authorities. The Star Shower is the main product making headlines in the US over this issue, but even if you aren't using one, knockoff products can have a similar effect. The makers of Star Shower, to their credit, include a notice in the user manual with instructions on proper use, and advice to keep the lights out of the sky and aimed squarely at your home.
If you live near an airport, heliport, or have any air traffic over your home, take the time to properly set up your lights, then check them again after dark. Products like the Star Shower are designed to be aimed at the side of your house, but it's easy to mistakenly point them too high or too close (so that they shine upward).The fix for this is easy: make sure your laser lights are pointed entirely at your home instead of the sky.