Which part of the aircraft has the largest effect on induced drag?

The wing tip has the largest effect on induced drag because it is where a significant aerodynamic phenomenon occurs: the development of vortices. These vortices are a natural byproduct of lift generation. As air flows over the wing, high-pressure air from beneath the wing spills over to the low-pressure region above the wing, creating vortices at the wingtips.

These vortices induce downward air movement behind the wing, leading to an increase in induced drag. The drag increases as the angle of attack of the wing increases, which is commonly experienced during lower speeds, such as during takeoff and landing.

Additionally, the wingtip design can significantly influence the strength and size of these vortices. Various wingtip modifications, like winglets, are employed to reduce this induced drag by controlling the flow of air and minimizing the vortices. Therefore, among the options provided, the wing tip plays the most crucial role in the generation of induced drag, making it the correct choice.