Lasers don't "see", rather they emit photons. You could use fluorescent paints on the boards, the plane could shine a weak 405nm beam to fluoresce them, but you would need sophisticated (read heavy) electronics and a color camera to determine the color and move the appropriate RC servo on the plane. All this stuff might be too heavy for an RC plane, unless you are allowed a big plane. Is this a school or university activity? Putting lasers on a plane is asking for terrorism charges in most jurisdictions. One nasty cop could give you a very bad legal headache. if it is an educational thing, and eye safety is covered, you might be OK. There might be better ways than using a laser ... What about a waypoint system with short range radio transmitters at each turn point, so the plane's computer knows which way to turn depending on the frequency of the transmitter. Computer starts the plane on its course and then looks for and heads to the first tx, then turns when the tx signal is strongest (when tx is under the plane). Two differnt frequencies would give left and right.
