Which marking indicates a non-movement area at an airport?

The marking that indicates a non-movement area at an airport is the boundary marking. This type of marking delineates the separation between movement areas, which are areas where aircraft are allowed to taxi and depart, and non-movement areas, where taxiing is restricted. Boundary markings are typically solid yellow lines and provide a clear visual cue to pilots and ground personnel that they are entering or exiting a non-movement area.

Understanding the purpose of boundary markings is essential for maintaining safety on the airfield. They help prevent unauthorized access to movement areas, reducing the risk of collisions between aircraft and ground vehicles. This is especially critical in busy airport environments where clear communication and visual identifiers are necessary for operational safety.

The other options do not serve this specific purpose. Specialized hold position markings are used to signify where aircraft must stop in relation to runways or taxiways to prevent incursions. Zipper markings and envelope markings are not standard airport markings, but they may refer to other forms of ground traffic control or visual aids that do not specifically indicate non-movement areas.