What is an airfoil?

An airplane wing has a special shape called an airfoil.
As a wing moves through air, the air is split and passes above and below the wing. The wing’s upper surface is shaped so the air rushing over the top speeds up and stretches out. This decreases the air pressure above the wing. The air flowing below the wing moves in a straighter line, so its speed and air pressure remain the same.
Since high air pressure always moves toward low air pressure, the air below the wing pushes upward toward the air above the wing. The wing is in the middle, and the whole wing is “lifted.” The faster an airplane moves, the more lift there is. And when the force of lift is greater than the force of gravity, the airplane is able to fly.

 

Examples of airfoils in nature and within various vehicles. Though not strictly an airfoil, the dolphin fin obeys the same principles in a different fluid medium.

To learn how an airfoil works please click on the link below:-

How an airfoil works is best illustrated in this report.