Which factor does NOT significantly affect lift and drag?

Engine speed does not significantly affect lift and drag because lift and drag are primarily influenced by aerodynamic principles related to the aircraft's shape, angle of attack, wing area, and the density of the air through which the aircraft is moving.

Lift is generated when the airflow over and under the wings creates a pressure difference, and this is highly dependent on the angle of attack, wing area, and air density. The angle of attack, or the angle between the chord line of the wing and the oncoming airflow, directly influences the amount of lift produced. Similarly, a larger wing area can create more lift, and greater air density increases the amount of air molecules interacting with the wings, thus enhancing lift.

While engine speed influences thrust, which can affect the overall performance of the aircraft and the conditions under which lift and drag are experienced, it does not directly alter the fundamental aerodynamic forces acting on the wings themselves. Therefore, when considering the primary factors that impact lift and drag directly, engine speed is not one of them.