Airport Codes Table
| # | IATA | Airport | City | Enplaned 2024 |
|---|---|---|---|---|
| 1 | ATL | Hartsfield-Jackson Atlanta International | Atlanta, GA | 61,163,469 |
| 2 | DFW | Dallas/Fort Worth International | Dallas-Fort Worth, TX | 39,109,844 |
| 3 | DEN | Denver International | Denver, CO | 38,314,105 |
| 4 | ORD | Chicago O'Hare International | Chicago, IL | 35,565,504 |
| 5 | LAX | Los Angeles International | Los Angeles, CA | 34,838,868 |
| 6 | CLT | Charlotte Douglas International | Charlotte, NC | 27,297,730 |
| 7 | LAS | Harry Reid International | Las Vegas, NV | 26,563,847 |
| 8 | PHX | Phoenix Sky Harbor International | Phoenix, AZ | 24,967,153 |
| 9 | MCO | Orlando International | Orlando, FL | 24,058,331 |
| 10 | SEA | Seattle-Tacoma International | Seattle, WA | 22,634,634 |
| 11 | MIA | Miami International | Miami, FL | 22,344,559 |
| 12 | IAH | George Bush Intercontinental | Houston, TX | 21,861,493 |
| 13 | JFK | John F. Kennedy International | New York, NY | 20,847,112 |
| 14 | EWR | Newark Liberty International | Newark, NJ | 20,564,656 |
| 15 | SFO | San Francisco International | San Francisco, CA | 20,327,631 |
| 16 | DTW | Detroit Metropolitan Wayne County | Detroit, MI | 15,592,269 |
| 17 | BOS | Boston Logan International | Boston, MA | 15,253,050 |
| 18 | MSP | Minneapolis-St Paul International | Minneapolis-St Paul, MN | 15,153,000 |
| 19 | PHL | Philadelphia International | Philadelphia, PA | 13,610,000 |
| 20 | BWI | Baltimore/Washington International Thurgood Marshall | Baltimore, MD | 12,795,000 |
The three-letter airport code is the rare piece of travel infrastructure that has outlived its own logic. IATA codes began as a shorthand for the rail stations airlines served, then grew by accretion: some are obvious (ATL, DEN, MIA), some preserve a city's old name (ORD is a compress of 'Orchard Field', the orchard-farm airstrip Chicago O'Hare replaced), and some are honest mistakes kept for typography's sake - New Orleans kept MSY from 'Moisant Stock Yards', the pioneer aviator's old airstrip.
The ranking below is the load-bearing fact: the top 20 US airports handle roughly half of all domestic air traffic, and the head is heavier than the rest combined intuition suggests. Hartsfield-Jackson Atlanta enplaned about 61 million passengers in 2024 - roughly 168,000 people a day - riding its position as Delta's fortress hub at the geographic center of the eastern half of the country. The next tier (Dallas-Fort Worth, Denver, Chicago O'Hare, Los Angeles) runs 35-39 million apiece, and the list thins to 12.8 million by Baltimore.
Reading the table by code beats reading it by city: the code is what appears on your boarding pass, your bag tag and your fare search, and hubs are named for airlines first - ATL (Delta), DFW (American), DEN (United) and ORD (United's co-hub) are route systems, not just cities. That is also why two Washington-area and two Houston-area airports can sit 20 rows apart: the code encodes the facility, the airline's schedule encodes the competition.
How to use
- Find your row: the table ranks the 20 busiest US airports by 2024 enplaned passengers (boardings, not total movements) - ATL leads at about 61.2 million, and the top five (ATL, DFW, DEN, ORD, LAX) all clear 34 million.
- Use the code column for booking hygiene: codes one keystroke apart can be three hours apart - MIA (Miami) versus MKE (Milwaukee), ORD (O'Hare) versus MDW (Midway, Southwest's Chicago field) - and fare searches that match city rather than code routinely hide the second airport.
- Read hub logic from the ranking: a megahub near the top means one airline's connections dominate (Delta at ATL and MSP, American at DFW and CLT, United at DEN, ORD, IAH and EWR) - if your itinerary connects through two hubs of the same carrier, the table explains why the fare was cheaper and the walk was longer.
Frequently asked questions
What does the airport code ORD stand for?
O'Hare's code honors what the airfield was before it was O'Hare: 'Orchard Field', a Douglas aircraft plant and orchard-strip airstrip the city annexed; the OR- prefix stuck when the field became a commercial airport in 1949 (renamed for Medal of Honor aviator Edward 'Butch' O'Hare). The same fossil logic explains MSY (Moisant Stock Yards, New Orleans) and MCI (Mid-Continent International, Kansas City).
What are the busiest airports in the US?
By 2024 enplaned passengers: Hartsfield-Jackson Atlanta (about 61.2 million) leads by a wide margin, followed by Dallas-Fort Worth (39.1M), Denver (38.3M), Chicago O'Hare (35.6M) and Los Angeles (34.8M). Counting total passengers including connections, Atlanta has been the world's busiest airport for most years since 1998 - the connections model, not local population, drives the top of this table.
Why do some airport codes start with letters that don't match the city?
History, in three layers: early codes copied rail/telegraph station identifiers (two letters), IATA later standardized to three, and Canada-mexico coordination reserved the K prefix for the contiguous US - so Los Angeles kept LAX rather than clashing, Washington's Dulles took IAD after WAS-family codes were needed for the capital's multiple fields, and Toronto's YTZ still wears the T-z shorthand of its island ferry era.
What is the difference between enplanements and total passengers?
Enplanements count boardings only; total passengers count boardings plus arrivals. The table uses enplanements (the FAA/BTS hub metric), which is why Atlanta shows ~61 million here but about 123 million 'total passengers' in press releases - the connection-heavy megahubs look most different between the two measures, and comparing across tables without checking which metric is used is the most common ranking error.
Why is Atlanta's airport so much busier than bigger cities?
Hub economics: Atlanta sits within a two-hour flight of roughly 80% of the US population, owns Delta's largest connection bank, and has no competing large airport in-state - so it feeds connecting traffic the way Dallas (DFW plus Love Field) or Washington (DCA plus IAD plus BWI) cannot concentrate. The pattern generalizes: the top of the table is a map of airline route systems, not of city size.