Current regulations require owners to report the sale of an aircraft, the scrapping or destruction of an aircraft, or a change in mailing address, but many owners have not complied with those requirements. Re-registration of all U.S. civil aircraft by Dec. 31, 2013 will enhance the database with current data derived from recent contact with aircraft owners. The new regulations also will ensure that aircraft owners give the FAA fresh information at least once every three years when they renew their registration. The FAA will cancel the N-numbers of aircraft that are not re-registered or renewed.

An aircraft registration is a unique alphanumeric string that identifies a civil aircraft, in similar fashion to a license plate on an automobile. In accordance with the Convention on International Civil Aviation all aircraft must be registered with a national authority (such as the FAA  or Transport Canada), and furthermore, they must carry proof of this registration in the form of a legal document called a Certificate of Registration at all times when in operation. Most countries also require the aircraft registration to be imprinted on a permanent fireproof plate mounted on the fuselage for the purposes of post-fire, post-crash aircraft accident investigation.

Because airplanes typically display their registration numbers on the aft fuselage just forward of the tail, in earlier times more often on the tail itself, the registration is often referred to as the "tail number". In the United States, the registration number is also referred to as an "N-number", as it starts with the letter N.