Which statement about the lift to drag ratio in straight and level flight is correct?

The highest lift-to-drag ratio is a critical concept in aerodynamics, particularly in the context of achieving efficient flight conditions. The correct interpretation lies in understanding that the lift-to-drag ratio is defined as the amount of lift generated per unit of drag experienced by the aircraft.

In the context of straight and level flight, the lift-to-drag ratio is most favorable when the aircraft operates at its optimum angle of attack, which typically occurs close to the point where the aircraft is able to generate sufficient lift to maintain level flight without excess drag. This point usually aligns with balanced conditions, specifically where lift equals aircraft weight, making that flight configuration highly effective for efficiency.

If the lift were to be zero, the lift-to-drag ratio cannot be computed meaningfully; the aircraft would not be flying. Therefore, there cannot be a circumstance with a high lift-to-drag ratio with zero lift. This explains why the statement about the highest lift-to-drag ratio occurring when lift is zero is incorrect.

Statements regarding drag and lift indicate that the lowest drag is not necessarily at the peak of lift, as drag can behave differently based on the configuration and state of the aircraft (like speed and angle of attack). The relationship between lift and drag does not decrease