An aircraft includes an airfoil and a hinge member to rotatably couple the airfoil to a structure of an aircraft. The hinge member defines at least a portion of a rotational axis. The aircraft also includes an indexing mechanism coupled to the airfoil and configured to, in a first state, inhibit rotation of the airfoil about the rotational axis, and in a second state, to permit rotation of the airfoil about the rotational axis between a first position and a second position that is angularly indexed relative to the first position. The aircraft further includes an actuator to selectively change a state of the indexing mechanism from the first state to the second state, from the second state to the first state, or both.