Aircraft security refers to the measures and protocols implemented to protect aircraft from threats such as terrorism, sabotage, and other unlawful acts. This includes screening passengers and luggage at airports, using advanced technology like X-ray machines and metal detectors, and employing trained security personnel to monitor activities. In addition to passenger screening, airlines and airport authorities work together to secure the aircraft itself. This involves regular inspections, access control to restricted areas, and surveillance systems to deter unauthorized access. Overall, aircraft security aims to ensure the safety of passengers, crew, and the aircraft during all phases of flight.