Final answer:
The Certificate of Aircraft Registration expiration varies by the aviation authority, with the FAA's certificate expiring after three years, requiring timely renewal for legal aircraft operation.
Step-by-step explanation:
The Certificate of Aircraft Registration expires at varying times depending on the country's aviation authority and specific regulations. In the United States, for example, the certificate issued by the Federal Aviation Administration (FAA) typically expires after three years. It is essential for aircraft owners to be aware of their certificate's expiration date and renew it timely to ensure the legality of the aircraft's operation.