Does every single aircraft have a unique registration mark or number? If, for example, 2000 Boeing 777 units were produced, do they have their own registration number? And how is that registration number regulated? Who keeps the number? What is that registration intended for? Registration number


1 Answer 1


Yes, every aircraft has a registration number--or "tail number" since it is commonly painted on/near the tail. This links each make/model/serial combination to a specific owner, similar to a car's license plate.

Each country assigns tail numbers with that country's unique one-, two- or three-letter prefix(es), e.g. "N" for the USA and "XA" for Mexico, followed by some number of letters and/or digits according to their chosen scheme. Some countries allow requesting a specific number not already in use (or reserved), similar to vanity license plates.

For non-commercial flights, a plane's tail number is used as its radio callsign since it's guaranteed to be unique. Commercial flights typically use the carrier's callsign plus flight number.

  • $\begingroup$ Thank you my friend. You made the explanation easy. $\endgroup$ Commented Jan 23, 2019 at 1:57
  • $\begingroup$ So clearly, it is belong to a country, not to an airline company, right? $\endgroup$ Commented Jan 23, 2019 at 1:58
  • $\begingroup$ Yes, in the same way a car license plate number "belongs" to the country that assigns it--even for commercial vehicles. $\endgroup$
    – StephenS
    Commented Jan 23, 2019 at 3:25
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    $\begingroup$ Not only countries has a prefix (United Nations: 4U), and not all countries have only one prefix (Brazil has PP to PU), see: en.wikipedia.org/wiki/List_of_aircraft_registration_prefixes $\endgroup$ Commented Jan 23, 2019 at 14:08
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    $\begingroup$ @GiacomoCatenazzi Edited to account for multiple prefixes. The UN only uses its prefix for its own aircraft, i.e. no other party can register its planes with them, so it's not worth the added complexity. $\endgroup$
    – StephenS
    Commented Jan 23, 2019 at 16:38

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