Your aircraft registration number is a unique identifier assigned by the FAA that appears on your plane's fuselage and tail, similar to a vehicle license plate

The N-number (or tail number) is the aircraft's permanent identifier in the United States. It always starts with the letter N, followed by up to five characters that can be numbers, letters, or a combination. For example, N12345 or N1AB. This number is painted on the outside of the aircraft and is also recorded in the FAA's aircraft registry, a public database you can search online.

Every aircraft registered in the United States has one, whether it's a small Cessna, a commercial airliner, or a helicopter. The N-number stays with the aircraft throughout its life, even if it changes owners. You'll need this number for maintenance records, insurance, flight operations, and any official FAA communication about that specific plane.

Key Takeaways

  • The N-number is a five-character identifier starting with N, painted on the aircraft's exterior and used by the FAA to track ownership and registration status.
  • You can search the FAA's N-Number Inquiry database on the FAA website to find registration details, owner information, and aircraft specifications for any registered plane.
  • The registration certificate (Form AC 7-1) is the official document proving ownership and must be carried aboard the aircraft during flight.
  • Registration lasts three years and requires renewal through the FAA; you'll receive a renewal notice before expiration, similar to vehicle registration renewal.
  • If you own an aircraft, the N-number appears on your bill of sale, insurance documents, and maintenance logs, making it essential for all ownership records.

How the FAA assigns and formats N-numbers

The FAA assigns N-numbers sequentially as new aircraft are registered. The format allows for flexibility: you might see N1 (the shortest possible), N12345 (five digits), N1A (a number followed by a letter), or NA1234 (letters and numbers mixed). The FAA has specific rules about which combinations are available and which are reserved, but as an aircraft owner, you don't choose your N-number during initial registration—the FAA assigns it to you.

However, if you want a different N-number after registration, you can request a vanity N-number or preferred N-number through the FAA's assignment process. This is similar to personalized license plates for cars. You submit a request with your preferred number, and if it's available and meets FAA rules (for example, it can't spell out anything offensive or misleading), the FAA may reassign your aircraft to that number. There is no fee for this request, but availability is limited and the process can take several weeks.

Where to find your aircraft's N-number

The N-number is painted on both sides of the fuselage (the aircraft's body) and on the tail in large, easily visible letters. If you're looking at an aircraft in person, you'll see it clearly marked. If you're researching an aircraft you don't own, you can search the FAA's public database.

The FAA N-Number Inquiry tool is available on the FAA's website and allows you to search by N-number, owner name, or aircraft type. This database is public and contains information such as the aircraft's make and model, year of manufacture, current registration status, and owner details. If you own the aircraft, this is also where you'll verify that your registration is current and active.

The aircraft registration certificate and what it proves

When you register an aircraft with the FAA, you receive a Certificate of Aircraft Registration, also called Form AC 7-1. This document is the official proof that you own the aircraft and that it is registered with the FAA. It includes the N-number, the aircraft's make and model, the serial number, your name and address as the registered owner, and the date of registration.

You are required to carry this certificate aboard the aircraft during flight. It serves the same purpose as a vehicle registration card in your car—it proves the aircraft is legally registered and that you have the right to operate it. If you sell the aircraft, the new owner must register it in their name and receive a new certificate. The old certificate becomes invalid once the transfer is complete.

Registration validity and renewal timing

Aircraft registration is valid for three years from the date of issue. The FAA will send you a renewal notice approximately 90 days before your registration expires. Unlike some vehicle registrations that require an in-person visit to a local office, aircraft registration renewal is handled entirely through the FAA by mail or online.

To renew, you'll submit Form AC 7-1 (the renewal version) along with proof that the aircraft has passed its required inspection. For most general aviation aircraft, this means a current Airworthiness Certificate, which confirms the plane is safe to fly. You'll also need to pay the registration fee, which varies depending on the aircraft's weight. The FAA processes renewals and sends you a new certificate valid for another three years.

If your registration expires and you don't renew it, the aircraft cannot legally fly. The N-number remains reserved in the FAA database for a period, but you cannot operate the aircraft until registration is restored.

How N-numbers differ from other aircraft identifiers

The N-number is distinct from other numbers you'll see on an aircraft. The serial number (also called the manufacturer's serial number or MSN) is assigned by the aircraft's builder and identifies that specific airframe. It never changes, even if the aircraft is re-registered or sold. The serial number is used for maintenance records and parts tracking.

The mode C code (or transponder code) is a four-digit number used by air traffic control radar to identify the aircraft during flight. This is temporary and changes depending on the flight and airspace. The N-number, by contrast, is permanent and publicly visible on the aircraft itself.

For commercial aircraft, you may also see an airline's flight number displayed (like "United 447"), but this is not the aircraft's identifier—it's the flight's designation. The same aircraft will have different flight numbers on different routes and days. The N-number is what the FAA uses to track the aircraft itself, regardless of which airline operates it or what flight it's on.

What happens to the N-number when you sell the aircraft

When you sell an aircraft, the N-number stays with the plane, not with you. The new owner must register the aircraft in their name with the FAA. During this transition, the aircraft's registration status changes from your name to the new owner's name in the FAA database, but the N-number remains the same.

The bill of sale should include the N-number, the aircraft's serial number, and the current registration certificate number. This documentation protects both you and the buyer by creating a clear record of the transfer. The new owner has 60 days to submit their registration paperwork to the FAA; during this period, the aircraft can still fly under the old registration, but the new owner should begin the registration process when ready.

Frequently Asked Questions

Can I look up who owns an aircraft if I know the N-number?

Yes. The FAA's N-Number Inquiry database is public, and searching by N-number will show you the registered owner's name, address, and aircraft details. This information is available to anyone and is used by insurance companies, mechanics, and the general public to verify aircraft ownership and registration status.

What if an aircraft's N-number is damaged or faded?

The N-number must be clearly visible and legible at all times. If it's damaged, faded, or illegible, the aircraft is not airworthy and cannot fly legally. You must repaint the N-number to FAA standards before the aircraft can return to service. The FAA specifies the minimum size, font, and contrast required for the N-number to be visible from a safe distance.

Is the N-number the same as the aircraft's call sign?

No. The N-number is the aircraft's permanent registration identifier. The call sign is what pilots use when communicating with air traffic control and is typically based on the N-number but may be abbreviated. For example, an aircraft with N-number N12345 might use the call sign "Twelve-Three-Four-Five" or "Niner-Two-Three-Four-Five" in radio communications.

Do I need to register an aircraft if I'm not flying it commercially?

Yes. Any aircraft that will be flown in U.S. airspace must be registered with the FAA, regardless of whether it's used for personal, business, or commercial purposes. Even if you own a small ultralight or experimental aircraft, registration is required before you can legally fly it.

Can I transfer an N-number to a different aircraft I own?

No. Each aircraft has its own unique N-number assigned by the FAA, and that number stays with that aircraft for its entire life. You cannot move an N-number from one aircraft to another. If you own multiple aircraft, each one has its own distinct N-number and registration certificate.