So lift is due to pressure differentials on the top side of a foil? It's just that the traditional reasoning as to why those those differentials formed (air moving at a faster speed over the top) was not accurate?
Not quite. The air does move faster over the top of the airfoil, and this does result in lower pressure there. However, explanations related to this being due to the difference in length of path are completely wrong. The air molecule that goes over the top gets to the trailing edge long before a similar air molecule that goes under the airfoil. The explanation in the paper is that this difference is primarily due to the circulation flow around the airfoil, and he goes into a lot of detail about this flow.
