Aerospace vehicle leading edge slat devices and corresponding methods are generally disclosed herein. One aspect of the invention is directed toward an aerospace vehicle system that includes an airfoil having a leading edge. The system further includes a first flow body fixedly coupled to the airfoil to form at least one gap between the leading edge of the airfoil and the first flow body. A second flow body can be coupled to the airfoil and can be movable between at least a retracted position where the second flow body is positioned to at least approximately aerodynamically seal the at least one gap, and an extended position where the second flow body is positioned to allow fluid flow through the at least one gap.