There are two primary theories to the production of lift - Bernoulli's Principle andNewtons Third Law. Bernoulli determined that, as fluid increased speed traveling through thenarrower part of the tube, the pressure decreased.This concept of decreasing pressure whenfluid speeds up is the basis for the use of his theory in regards to lift.As the airspeed increasesthe pressure decreases, creating unequal pressure on the top and bottom of the airfoil and causingthe high-pressure air to attempt to equalize with that low pressure air, causing lift to be created.Newton's Third Law, equal and opposite reaction, can tell us that as you apply an increase inairspeed, the wings are forced upwards because they have a slight tilt to them in relation to therelative wind.That causes air to deflect downwards when striking the airfoil, thus causing theairfoil to move upwards