Which of the following can be adjusted to improve aircraft stability during flight?

Adjusting the center of gravity is a fundamental factor in enhancing an aircraft's stability during flight. The center of gravity (CG) refers to the point where the aircraft's mass is balanced and if it is positioned correctly, it can significantly improve stability. When the CG is within the prescribed limits, the aircraft will tend to return to a stable flight condition following disturbances, such as turbulence or pilot input.

If the center of gravity is too far forward or too far aft, it can lead to poor stability characteristics, making the plane harder to control or resulting in increased difficulty in recovering from unusual attitudes. For example, a forward CG can lead to increased stability in pitch, while an aft CG can make the aircraft more susceptible to pitch oscillations and less stable overall.

In contrast, while other factors like throttle position, altitude, and wing flaps influence the operation and performance of the aircraft, they do not fundamentally alter the stability characteristics related to the aircraft's design and mass distribution like the center of gravity does. Throttle affects speed and engine performance, altitude relates to air density and performance in general, and wing flaps primarily contribute to lift and drag characteristics rather than overall stability.