What requirement applies to flights between the United States and Mexico regarding security searches?

Flights between the United States and Mexico are subject to stringent security regulations that mandate thorough security measures to ensure passenger safety and compliance with international aviation standards. The requirement for a full search being completed is designed to mitigate threats, enhance security protocols, and maintain the safety of everyone on board.

Full searches are crucial in identifying any potential risks that could be posed by passengers or their belongings. This measure not only includes the scanning of baggage but also involves screening personal items and conducting pat-downs if necessary. These comprehensive security checks align with the broader framework that governs aviation security, emphasizing the importance of vigilance in the protection of air travel.

The other options suggest less rigorous search requirements, which do not reflect the actual security practices enforced for transnational flights, particularly given the complexities of air travel security.