The operation of airfoils is non-intuitive and many (event most pilots) hold misconceptions about how they work. That does not mean that the physics is not well

The operation of airfoils is non-intuitive and many (event most pilots) hold misconceptions about how they work. That does not mean that the physics is not well understood by those who design them. There maybe a few gaps (particularly for supersonic flight) still being explored, but in general it's inaccurate to claim that we don't know how airplanes work.