United States Airport Codes: What the Letters on Your Ticket Mean

United States airport codes are the short letter sets printed on boarding passes, bag tags, and departure boards. They keep one airport distinct from a similarly named city, a second airport in the same metro area, or another facility that shares a similar label.

What United States airport codes are

The FAA calls these codes location identifiers. Per the FAA location-identifier publication, a location identifier takes the place of the name and location of an airport, navigation aid, weather station, and manned air traffic control facility in air traffic control, telecommunications, computer programming, weather reports, and related services.

That means the official system is wider than the three letters a passenger sees while booking. A code in an aviation database may identify a weather site or navigation aid, not a commercial terminal you can book.

Code formats travellers see

Format	What the FAA source establishes	Travel tip
Three-letter FAA identifier	The FAA assigns three-letter identifiers (except those beginning with N, W, Y, and Z) for the United States and its jurisdictions.	Match the letters to the full airport name on your ticket.
Other FAA character formats	The FAA also assigns three- and four-character identifiers and five-letter name codes.	Do not treat every FAA identifier as a bookable passenger airport.
Metropolitan-area identifier	Existing metropolitan codes are not exchangeable with airport codes at the same location.	Confirm the specific airport, not only the city or region.
Facility name or city search	The FAA Location Identifiers Search Tool can search partial idents, names, and locations.	Use it when the letters alone are ambiguous.

How to look up a United States airport code

1. Read the pair on your documents. Note both the code and the full airport name on the reservation or boarding pass.
2. Compare every leg. Connections can use different airports in one metro area. Confirm arrival and departure codes separately.
3. Search the FAA tool. The FAA Location Identifiers Search Tool provides a quick search of location identifiers and can search partial idents, names, and locations.
4. Use the Location ID Database when needed. The FAA Air Traffic Control System Command Center also publishes a Location ID Database query for identifier, facility, and city or state fields.
5. Confirm live terminal details elsewhere. An airport code identifies the facility. Gate and terminal information come from the airline or official airport site.

Why the letters may not match the airport name

Established three-letter identifiers are considered permanent and will not be changed without strong justification, primarily concerning air safety. The original identifier will remain in effect, in most instances, even when a facility name changes. That is why some United States airport codes look unlike the name on the terminal facade.

Location identifiers are also not interchangeable from one airport to another, even within the same community. If you are choosing among airports that serve one city, treat each code as its own destination.

Airport code versus city or metro code

Some three-letter identifiers were assigned in the past to designate a metropolitan area where a principal city is served by more than one airport. The FAA says no further assignment of metropolitan codes is contemplated, and existing metropolitan codes are not exchangeable with airport codes at the same location.

When a search result lists a region first, open the specific airport name before you book parking, schedule a pickup, or tell a rideshare where to go.

How these codes relate to the wider airport network

The FAA National Plan of Integrated Airport Systems (NPIAS) identifies nearly 3,300 public-use airports in the national airport system. It includes all commercial service airports, all reliever airports, and selected public-owned general aviation airports. A code may exist for a facility that is not an airline hub. For network size and maps, see how many airports are in the United States and the map of airports in the United States.

The FAA Air Traffic page reports 527 airport traffic control towers. That tower count is not a total of United States airport codes or of all airports.

Before you fly

• Match every code on the itinerary to the full airport name.
• Confirm each connection airport if the metro has more than one field.
• Look up unfamiliar identifiers with the FAA Location Identifiers Search Tool.
• Save the verified airport name, code, and terminal plan for offline use.

Identifier assignments and operating details can change. Confirm the code and current airport information with the FAA, the airline, or the official airport source before flying. For terminal flow after you land, see how to navigate an airport and the companion guide to United States of America airport codes.