The Mystery Behind Airport Codes – How Are They Created?

IATA Airport Codes Ottawa, Doha, London Heathrow, Sydney, Baltimore, Miami, Beijing Capital, Stockholm Arlanda

Over 3.7 billion people travelled around the world annually. Many of these travellers wondered why airport codes are three letters long and how are they created. This post uncovers the mystery of airport codes and showcases how they can be used in unique way in retail and marketing.

Airport Codes


Airport codes was invented to add convenience for pilots to identify locations in the 1930s.  In the US, two-letter code from the National Weather Service (NWS) was used. As the country’s population increased and more airports were built, the two-letter code system did not have the capacity to manage all the new airports.  That was where the three-letter system of today was born.

This system allows for 17,576 unique combinations and is governed by International Air Transport Association (IATA) through Resolution 763 – Location Identifiers found in its baggage standards (refer to the list of these standards here). The characters are now displayed on baggage tags, mobile applications, displays, city marketing, etc as a way to identify the city/location.

The IATA codes are published bi-annually in its Airline Coding Directory which can be found here and is administered in Montréal, Canada. Many travellers associate these codes only for airports but they are also used for railway stations around the world to ease convenience when airlines codeshare with railway companies. Click here for a list of Amtrak station codes used in the US and Canada and here on how airlines and railways partner together.

Behind The Scenes

1 . At the beginning, when cities/locations applied for codes, the first three letters were used. For example, Amsterdam Schipol Airport’s code is AMS and Singapore Changi Airport’s code is SIN.

IATA code for Amsterdam and Singapore
IATA code for Amsterdam and Singapore – Information taken from IATA’s website. Infographic created by Experience The Skies.


2. Some like to use part of its location’s name when the first three letters were unavailable. For example, 

IATA code for Hong Kong and Johannesburg
IATA code for Hong Kong and Johannesburg – Information taken from IATA’s website. Infographic created by Experience The Skies.


3. Some US airports tagged X behind its NWS name. For example, both Los Angeles and Portland kept their two letter code LA / PD and included an X in the end after 1947.

IATA code for Los Angeles and Portland
IATA code for Los Angeles and Portland – Information taken from IATA’s website. Infographic created by Experience The Skies.

4. Two popular travellers destinations are Chicago and Orlando (both in the USA). Yet, the international airport codes for both do not follow the naming conventions above. Why?

IATA code for Chicago O'Hare and Orlando
IATA code for Chicago O’Hare and Orlando – Information taken from IATA’s website. Infographic created by Experience The Skies.

Chicago main airport used by both American Airlines (AA) and United Airlines was replaced to O’Hare International Airport in 1949 to Medal of Honor recipient Edward O’Hare. The airport however retained the code based on its original name Orchard Field Airport.

In Orlando’s case,  its international airport used to be a military field called McCoy Airforce Base honoring the late Michael Norman Wright McCoy.

Other codes that use the airport’s name in its code include: Paris Charles de Gaulle Airport (CDG) and London Heathrow Airport (LHR).


5. Many Canadian airports started its life with a two-letter code. When the IATA three-letter system debuted, Canadian regulators decided to add a Y in front of all airport codes.

IATA code for Toronto and Vancouver
IATA code for Toronto and Vancouver – Information taken from IATA’s website. Infographic created by Experience The Skies .

Vancouver International Airport retained part of its name and added the Y in front it to form YVR. Naturally, one would think that Toronto Pearson International Airport would have something like YTO as its code. That airport’s code is YYZ because there are more than one airports in this city (YYZ and YTZ for Billy Bishop Toronto City Airport) and YTO was used to designate the metropolitan area.

Similar concept is applicable for Chicago with CHI (2 airports-ORD/MDW), New York City with NYC (3 airports-JFK/LGA/SWF) and London with LON (5 airports-LHR/LGW/LTN/LCY/STN).

Want to know more about origins of airport codes? Follow this link to It has stories for over 1000 airport codes around the world which is great for curious travellers and educators.

Airport Codes
Airport Codes   Source: .


As flying becomes more popular, retailers are finding ways to attract travellers with unique airport code related merchandise. Three of the most known retailers include: Airport Tag, Pilot and Captain and Aviate.

Bed Sheet by Airport Tag

Airport Code Bed Sheet Collection by Airport Tag

Pilot and Captain
Airport Code Tee Shirts by Pilot and Captain


Baseball Caps By Aviate
Airport Code Baseball Caps by Aviate

Airlines and airports have a great marketing opportunity to commission airport code pieces to highlight their services and products around with world.  One example was United Airlines who commissioned unique amenity kits for premium cabin passengers to showcase some of the airports it served. The first series included eight domestic US hub airports it operated from after the merger with Continental Airlines was completed. Of the eight, CLE is no longer designated as a hub and the airline left JFK and focused entirely at EWR for its New York traffic.

United Airlines Limited Edition Amenity Kits
Limited Edition Amenity Kits (2015)      Source: United Airlines

The second wave included one domestic – HNL and seven international airports -DXB (which the airline does not serve currently), PEK, FRA, RIO, HKG,  LHR, and SYD. These amenity kits are now considered collector items and unopened ones could sell for US$24.99 and up on eBay.

Comment below or contact us at to share products or marketing ideas relating to airport codes. We might post them at a later date.

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