What security measure must all cargo and mail undergo before being loaded onto an aircraft?

All cargo and mail must undergo security controls before being loaded onto an aircraft to ensure the safety and security of the flight. This requirement is part of aviation security regulations that are designed to prevent any potential threats from accessing the aircraft. Security controls can include screening processes such as x-ray inspections, physical searches, or utilizing trained detection teams to identify any prohibited items or threats.

Labeling, while important for identification and tracking purposes, does not ensure security on its own. Insurance verification and size checks are also important aspects of cargo management but do not address the essential need for security measures specifically designed to mitigate risks associated with air transport. Therefore, applying security controls is a fundamental step in protecting aviation operations from malicious acts.