An actuation and extension mechanism for aerodynamically high-lift devices such as a wing leading edge slat or a wing trailing edge flap; wherein an aerodynamic panel is connected to one end of an extendible track member that is supported and guided by its other end through rollers fixedly mounted to wing rib structure. The track member incorporates a separate rack gear segment internally thereof as part of the extension or retraction mechanism and this combination of track and gear segment provides the primary support and drive means to the high-lift device, without compromising the structural strength, safety, or operational reliability of said combination.