How does induced drag behave at varying airspeeds?

Induced drag is a result of the generation of lift and is fundamentally linked to the angle of attack and the lift produced by an airfoil. As airspeed increases, the amount of lift required for a given flight condition typically decreases, which in turn reduces the induced drag. This relationship results from the fact that at higher speeds, a lower angle of attack can generate the same amount of lift, thereby reducing the vortex strength and the resultant induced drag. Therefore, at higher airspeeds, the induced drag decreases, which aligns perfectly with the reasoning behind the correct answer.

In contrast, maintaining a constant induced drag, or suggesting that it increases or is unaffected by airspeed, does not accurately reflect the aerodynamic principles at play. Induced drag behavior is inherently linked to the relationship between lift and speed, emphasizing how it decreases as airspeed increases.