Lift
Lift is a force that is produced by the dynamic effect of the air acting on the airfoil, and acts perpendicular to the flight path through the center of lift (CL) and perpendicular to the lateral axis.
All other factors being constant, for every angle-of-attack (AOA) there is a corresponding airspeed required to maintain altitude in steady, unaccelerated flight.
As airspeed increase, lift also increases. If the angle of attack were held constant, and the aircraft speed up, the lift would increase and the aircraft would climb as a result of the increased lifting force. Therefore, to keep the aircraft straight and level (not accelerating upward), lift must be kept constant by reducing the AOA (usually lowering the nose).
