What is the primary purpose of an aircraft lavatory?

The primary purpose of an aircraft lavatory is to serve as a restroom for passengers. Aircraft lavatories are specifically designed to meet the hygiene and comfort needs of passengers during flights. They provide the essential facility for passengers to attend to their personal needs, which is particularly important on longer flights where access to such amenities becomes crucial for comfort.

While other functions mentioned, such as cargo storage or maintenance, may be relevant to the overall operation of an aircraft, they do not pertain to the specific role of the lavatory. The lavatory is dedicated solely to catering to the restroom needs of passengers, ensuring that they have access to necessary facilities while in the air. The design and operation of an aircraft lavatory are focused on optimizing space and functionality for this specific purpose, which underscores its importance in the in-flight experience.