Which of the following should be reported to the airport operations if found on the airfield?

Reporting unattended U.S. Mail to airport operations is crucial due to security and safety protocols associated with aviation environments. Unattended packages or mail can pose potential security threats, as they may contain hazardous materials or could be linked to illegal activity. Airport operations must investigate and assess any unattended items to ensure the safety of all personnel and passengers.

In contrast, while personal belongings can also be concerning, they generally do not carry the same level of urgency as unattended mail. Similarly, working equipment is typically accounted for by airport staff and does not require reporting unless it is malfunctioning or an operational hazard. Vehicles left parked may need attention, but unless they are obstructing operations or creating a safety issue, the priority usually falls on items that could endanger security first, like unattended mail.