The primary purpose of an airfoil is to generate , a force that acts at right angles to the airstream. This is achieved by creating a pressure difference between the upper and lower surfaces:
: Most airfoils are curved (cambered) so that air travels faster over the top surface than the bottom. According to Bernoulli's principle, faster-moving air creates lower pressure, resulting in upward lift.
Evolutionary understanding of airfoil lift - Springer Nature