Fins

Fins guide a rocket once it is moving fast enough for the air moving across the fin surfaces to steer the rocket.  Fins can be made of balsa wood, plywood, or plastic, and can be mounted on the surface of the airframe, or through the wall of the airframe with a tab secured to the motor mount inside the airframe.  Fins can also take the form of tube fins or ring fins, which also provide guidance, although they produce more drag than traditional fins.