Understanding US Airport Codes: A Complete Guide
The United States operates one of the largest and most complex aviation systems in the world, with over 5,000 public airports scattered across the country. Each of these facilities is identified by a unique three-letter code that serves as its aviation identity. These codes appear on your boarding pass, luggage tags, flight displays, and countless travel documents. Understanding how US airport codes work can make you a more informed traveler and help you navigate the American aviation landscape with confidence.
The Dual System: IATA vs FAA Codes
Unlike most countries where IATA (International Air Transport Association) codes are the primary identifiers, the United States actually uses two parallel coding systems. The FAA (Federal Aviation Administration) assigns its own three-letter identifiers to all US airports, while IATA assigns codes only to airports with scheduled commercial service. For major airports, these codes are often identical, but discrepancies can occur at smaller facilities.
For example, Los Angeles International Airport is LAX under both systems, and Chicago O Hare is ORD for both. However, some regional airports may have different FAA and IATA designations, which can occasionally cause confusion for travelers unfamiliar with the system.
Major Hub Airport Codes
The busiest airports in America serve as major hubs for domestic and international travel. Here are some essential codes every traveler should know:
East Coast Hubs
JFK – John F. Kennedy International Airport in New York City, named after the 35th President. EWR – Newark Liberty International Airport in New Jersey, serving the New York metropolitan area. LGA – LaGuardia Airport, primarily handling domestic flights in New York. BOS – Boston Logan International Airport. PHL – Philadelphia International Airport. DCA – Ronald Reagan Washington National Airport, with the D from its original name, Washington-Hoover Airport. IAD – Washington Dulles International Airport.
Southern and Midwest Hubs
ATL – Hartsfield-Jackson Atlanta International Airport, consistently the busiest airport in the world by passenger traffic. ORD – Chicago O Hare International Airport, derived from the old name Orchard Field. DFW – Dallas/Fort Worth International Airport. IAH – George Bush Intercontinental Houston. MIA – Miami International Airport. MSP – Minneapolis-Saint Paul International Airport.
West Coast Hubs
LAX – Los Angeles International Airport. SFO – San Francisco International Airport. SEA – Seattle-Tacoma International Airport. PHX – Phoenix Sky Harbor International Airport. SAN – San Diego International Airport. LAS – Harry Reid International Airport in Las Vegas.
How US Airport Codes Are Assigned
The assignment of airport codes in the United States follows certain patterns, though exceptions abound. Many codes are straightforward abbreviations of city names: DEN for Denver, BUF for Buffalo, STL for St. Louis. However, historical factors, naming conflicts, and practical considerations have created many codes that seem puzzling at first glance.
When a simple abbreviation is already taken, the FAA and IATA must find alternatives. This explains why Chicago O Hare is ORD (from its original name Orchard Field) rather than CHI, which was already assigned. Similarly, Indianapolis is IND rather than the taken alternatives.
Decoding Unusual US Airport Codes
Some US airport codes have fascinating backstories. MCO for Orlando comes from McCoy Air Force Base, which previously occupied the site. MSY for New Orleans derives from Moisant Stock Yards, named after early aviator John Moisant and the nearby stockyards. SNA for Santa Ana (Orange County) honors John Wayne, whose nickname was The Duke, though the airport is officially named after him.
Understanding these historical quirks makes US airport codes less mysterious and more meaningful. Each three-letter combination tells a story about aviation history, local geography, or the evolution of American air travel.
Tips for Travelers
When booking flights within the United States, always double-check airport codes, especially in metropolitan areas with multiple airports. New York City area travelers must distinguish between JFK, LGA, and EWR. Washington, D.C. visitors should know the difference between DCA, IAD, and BWI. Paying attention to these codes ensures you arrive at the correct airport and avoid costly mistakes.
