A seal plate (201) for maintaining a continuous aerodynamic surface between a fixed part (302) of an aerostructure such as an aerofoil (103) and a movable surface such as a spoiler (304) is provided. The seal plate (201) includes a resilient material such as fiberglass and has an aerodynamic surface (203). It is configured to be mounted to the fixed part (302) of the aerofoil along one edge (205) and to slidably seal with the control surface (304) at a second edge (207). The seal plate (201) is stepped and has a rigid lever (217) to engage behind the control surface (304) to bend the seal plate precisely according to movement of the control surface (304) and maintain the continuous aerodynamic surface.