The invention relates to a method for applying a film to a planar, especially air-impermeable substrate, comprising the steps: (a) feeding the planar substrate in a direction of feed towards an application device, (b) applying a film output by the application device to the planar substrate, and (c) sharply deflecting the planar substrate together with the film that is in contact therewith to a deflection area in a discharge direction different from the direction of feed. The invention also relates to a deflecting element for deflecting a planar substrate. Said element comprises at least one guiding surface adapted to guide a planar substrate and an additional guiding surface, forming an edge for sharply deflecting a planar substrate with the first guiding surface. At least one pressure channel extends through the deflecting element towards the edge and runs into at least one outlet opening in the area of the edge, said opening being configured in such a manner that the pressurized air discharged from said opening forms an air cushion which extends around the edge.