A plane is a tool for shaving off thin layers of wood, to make something flatter or thinner. Planes are often used to make a sticky door fit better. Planes have handles on them placed so you can get the best force, and the wood itself is shaved off with an adjustable blade under the plane. Planes work best going with the grain of the wood, not across it. As with many hand tools, you can also buy electric planes that don't require as much force to get them to work.