The problem of an inclined impact by an elastic plate on a thin liquid layer is considered. Evolution of the flow behind the plate is studied. The main input parameters are the position of the separation point of the liquid from the plate and the speed of the liquid under this point. The flow in the wake behind the plate is described by shallow water equations without gravity. Analytical formulae for the shape of the free surface behind the plate are derived. The study is focused on the possibility of the formation of jets arising from the wake perpendicular to the liquid layer. The problem is solved in two stages: before and after the formation of the first such a jet. The effects of the flow speed at the beginning of the wake, its time derivative, and the law of motion of the separation point on the formation of jets are investigated. The positions of the jets, their speeds and shapes are determined. Using the obtained results, mechanisms of the thin layer aeration behind the plate are discussed.