The usefulness of a signalling laser depends significantly on the environment you'll be in when you get into trouble. If you're in a woodland environment, the trees will likely block the very narrow laser beam. If you're in the west or mid-west, in a prairie, or mountain, or desert environment, a laser might make sense, depending on how far from civilization you roam. There are specially designed rescue lasers, that many pilots carry as part of their emergency kits. Also, some lasers offer a kind of spread-beam diffusing prism, that spreads the beam to cover a broad swath of sky. The thing to be very, very careful of when using a laser to signal an aircraft (or when using it at sea), is the pilot's vision. There are federal laws related to this, so do some research before casually using one in your adventures.