A Traveler's Quick-Reference Guide to US Airport Codes and Hubs

What Airport Codes Are and Why They Matter

Every commercial airport in the United States is assigned a three-letter IATA code — the identifier you see on boarding passes, baggage tags, and booking screens. These codes are standardized globally by the International Air Transport Association and are distinct from the four-letter ICAO codes used by air traffic control. As a traveler, the three-letter IATA code is the one that matters for trip planning.

Codes are not always intuitive. Some reflect a city's historical name (ORD for Chicago O'Hare, derived from Orchard Field), while others are straightforward abbreviations (LAX for Los Angeles). A few cities have multiple airports, each with its own code — knowing which code matches your terminal prevents costly mistakes at check-in.

Before your next trip, pair this reference with our domestic travel preparation checklist to make sure the rest of your departure logistics are covered.

Major US Hub Airports at a Glance

Hub airports are high-traffic facilities where an airline concentrates its connecting flights, making them critical nodes in the national route network. Flying through a hub typically means more scheduling options but also greater exposure to delays — a disruption at one spoke propagates quickly. The table below maps the most heavily trafficked US airports to their primary hub carriers.

Hub designations can shift as airlines adjust their networks. Always verify with your carrier before assuming a connection will operate smoothly through a particular hub.

Multi-Airport Cities and Secondary Airports

Several US metro areas are served by more than one airport, each with a distinct code. Booking the wrong airport can mean significant extra ground travel — or missing a flight entirely.

• New York metro: JFK (Queens), LGA — LaGuardia (Queens), EWR — Newark Liberty (New Jersey)
• Chicago metro: ORD — O'Hare (northwest suburbs), MDW — Midway (southwest Chicago)
• Los Angeles metro: LAX (Inglewood), BUR — Hollywood Burbank, LGB — Long Beach, ONT — Ontario, SNA — John Wayne/Orange County
• Washington, D.C. metro: DCA — Reagan National (Arlington, VA), IAD — Dulles (Loudoun County, VA), BWI — Baltimore/Washington (Maryland)
• San Francisco Bay Area: SFO (San Mateo County), OAK — Oakland, SJC — San José

When comparing fares across a metro area, always factor in ground transportation time and cost. A cheaper ticket into a secondary airport may cost more overall once parking, tolls, or rideshare fees are included. Our guide on hidden airline fees covers the full picture of travel costs beyond the base fare.

Practical Tips for Using Airport Codes

A few habits help travelers use airport codes accurately and avoid confusion:

1. Confirm the code on your itinerary matches the physical airport you plan to depart from — particularly in multi-airport cities.
2. Check terminal assignments. Some airports (LAX, JFK, ORD) have multiple terminals served by different airlines. Your code confirms the airport; your carrier and ticket confirm the terminal.
3. Use codes when searching. Entering a three-letter code directly into booking tools is more reliable than searching by city name, which can pull multiple airports.
4. Cross-reference for international connections. If you're connecting through a US hub to an international destination, confirm whether your inbound and outbound flights use the same terminal — not all hubs have a consolidated international terminal.

For a smoother security experience at any of these hubs, see our explanation of TSA PreCheck and Global Entry — both programs can meaningfully reduce wait times at busy airports. And if you've heard conflicting things about airport rules, common airport myths debunked separates fact from folklore.