The reason wings create lift is illustrated by Bernoulli's Equation:
Simple Newtonian Physics
Aerodynamic lift of a wing can be explained and calculated through simple application of Newtonian physics. Air flow following the contours of a wing in normal flight departs in a downward direction. In this redirection of flow, downward momentum is produced. Upward reaction force (or lift) must be equal, according to Newtonian physics, to the downward rate of change of air momentum. Inclination of a wing lower wing surface deflects some air downward there, while greater downward deflection is produced as flow follows the downwardly-curving upper surface. In the downwardly-curving flow, an upward pressure gradient exists which opposes atmospheric pressure to cause upper surface pressure reduction. Bernoulli's law is satisfied with velocity changes related to pressure changes when oncoming air accelerates over the wing leading edge into the reduced pressure above the wing and decelerates in encounter with increased pressure below the leading edge. The pressure difference also accelerates air upward around the leading edge. These accelerations occur in accordance with Bernoulli's law, but the greater upper surface velocity is more easily explained as resulting from pressure difference, rather than causing it as popular theories teach. (Craig)
The following is the equation for lift: