What is the primary function of a nacelle in an aircraft?

The primary function of a nacelle in an aircraft is to serve as the protective covering surrounding the aircraft engine. Nacelles are designed to streamline the aerodynamics of the aircraft, reducing drag and improving fuel efficiency. Additionally, they house engine components and systems, protecting them from the external environment while ensuring that the engine operates safely and efficiently. The design also allows for easier maintenance access to the engine.

This protective function is crucial, as it not only shields the engine from potential damage but also contributes to the overall performance of the aircraft. Nacelles are typically found in various configurations depending on whether the engines are mounted on the wings or the rear fuselage. Their importance in flight safety and engine performance highlights why this choice is the correct answer.