Lift-generating surfaces like wings, propellers, and rotors must be flown faster or at higher AOA to produce the same amount of lift at higher altitudes than at lower altitudes. This statement is _____.

The statement regarding lift-generating surfaces requiring greater speeds or higher angles of attack (AOA) to produce the same amount of lift at higher altitudes is true.

At higher altitudes, the air density decreases, which directly affects the lifting capability of airfoils. Lift is generated by the interaction of the wing (or other lift-generating surfaces) with the air, and it is influenced by several factors: the airspeed, the wing area, the air density, and the coefficient of lift, which is determined by the wing's AOA and shape. As altitude increases and air density drops, less air is available to create lift.

To counter this reduced lifting capability caused by lower air density, the aircraft must either increase its speed to maintain the same lift force or increase the angle of attack, which can allow the airfoil to generate lift more effectively under reduced density. This fundamental principle of aerodynamics is crucial for ensuring safe flight operations at various altitudes.

Given this understanding, the assertion is correct, as the requirement for increased speed or higher AOA to maintain lift at altitude is a foundational concept in aerodynamics and applies universally to various types of lift-generating surfaces.