Where does air exit the aircraft cabin?

Air exits the aircraft cabin primarily through vents and the lavatory. This is due to the design of the aircraft's environmental control systems, which utilize both supply and exhaust vents to maintain proper cabin pressure and air quality. Vents distribute fresh air throughout the cabin during flight, while certain systems allow for the removal of stale air and odors, particularly in lavatory areas.

Windows are sealed to maintain cabin pressure and therefore do not allow air to exit, eliminating that choice. The overhead compartments and galley are not designed for air exhaust; rather, they typically contain luggage and flight service equipment. Additionally, air does not exit through the cockpit in a way that would affect cabin pressure or airflow; rather, the cockpit has its own environmental controls and maintains a separate atmosphere from the cabin. Thus, vents and lavatories are the primary pathways for air to exit the cabin environment efficiently.