The wing occupies a certain amount of space. Fact.
When the wing moves from that space something must replace it. There cannot be nothing. Fact.
Solution = air.
That air is moved into place by the ambient airpressure. It flows smoothly down following the surface of the wing that is constantly moving out of the way. This movement of air that was stationery now has kinetic energy that has come from the plane moving. The plane keeps moving because of thrust provided by the powerplant. The wing doesn't pull it down, it is pushed down by surrounding air. No powerplant, potential energy from height.
Please note this is only addressing the top surface. The bottom surface is so obvious it shouldn't need explanation. Also it's my theory and not proven but I'm sticking with it until someone comes up with something simpler.