Air sticks to the wings and thus it changes its direction w.r.t the aeroplane. Wing shape is such that it maximizes air deflection before air eventually detache

Air sticks to the wings and thus it changes its direction w.r.t the aeroplane. Wing shape is such that it maximizes air deflection before air eventually detaches from the wing. Deflection means momentum change. Add Newton's third law and you've got it.