Lift is an aerodynamic force produced by the motion of an airplane's wing through the air. According to Bernoulli's principle, lift is generated because the airflow is faster and the pressure is lower over the curved top surface of the wing compared to the bottom. However, this explanation is flawed because a wing would still produce lift even if upside down. The correct explanation is that the wing exerts a downward force on the air and the air exerts an equal and opposite upward force on the wing according to Newton's Third Law of Motion.