Final answer:
Most manned aircraft and drones weighing more than 0.55 pounds must be registered with the FAA before operation in the NAS, providing aircraft identification and owner information for safety and compliance.
Step-by-step explanation:
The aircraft that must be registered with the FAA prior to operating in the National Airspace System (NAS) include almost all manned aircraft and certain unmanned aircraft systems (UAS) including drones that weigh more than 0.55 pounds (250 grams) but less than 55 pounds (approximately 25 kilograms), before considering payloads such as cameras. To register an aircraft, owners must provide information about themselves and the aircraft, and pay a registration fee. The process ensures that aircraft can be identified and traced, which is important for safety, national security, and compliance purposes.