What must crew members display while in secure airport areas?

Crew members are required to display a company ID above the waist while in secure airport areas to maintain visibility and ensure compliance with security protocols. The positioning of the ID is crucial; it allows for easy identification by airport security personnel and other staff members, which is important for maintaining a secure environment in sensitive areas of the airport.

The requirement for the ID to be displayed above the waist ensures that it is easily recognizable and accessible for quick verification, reducing confusion and enhancing overall security. This practice is in line with standard procedures in aviation security, emphasizing the importance of crew identification in secure locations. The other options, while they may present alternative ways to display identification, do not meet the specific requirement of being positioned above the waist, which is critical for visibility and adherence to security protocols.