The reasons for wing dihedral on a race car (operating in ground effect) are different than for an aircraft (operating out of ground effect). Dihedral in an aircraft wing promotes roll stability, albeit at a price in drag coefficient. Dihedral in a front wing on an open wheel race car is employed to reduce the turbulence effects from the front wing on the airflow path to the under tray. You want the center of the front wing high and out of the way, and the outer portions low so that the outer wing section and end plates can maximize the ground effect.
F1 wing airfoils are complex 3D profiles, and are set at an AoA that has them right on the edge of stall most of the time. Downforce is more critical than drag with an F1 car. However, with an aircraft, an airfoil that goes into stall is deadly.