Editing IATA airport code (section)

====Scarcity of codes====
Due to scarcity of codes (the three-character code is used by a maximum of 17,576 airports worldwide only), some airports are given codes with letters not found in their names:
*[[Alderney Airport|ACI]] for [[Alderney]], UK
*[[Bergen Airport, Flesland|BGO]] for [[Bergen, Norway]]
*[[Da Nang International Airport|DAD]] for [[Da Nang, Vietnam]]
*[[Pyongyang Sunan International Airport|FNJ]] for [[Pyongyang, North Korea]]
*[[John Glenn Columbus International Airport|CMH]] for [[Columbus, Ohio]], US

;Use of 'X' as a filler
The use of 'X' as a filler letter is a practice to create three-letter identifiers when more straightforward options were unavailable:<ref>{{Cite web |title=Airport Codes {{!}} Access Our Directory of Airport Code Data {{!}} OAG |url=https://www.oag.com/airport-code-directory |access-date=2024-11-08 |website=www.oag.com |language=en}}</ref><ref name=":0">{{Cite web |last=Morris |first=Mark |date=2022-12-15 |title=Why Is There an X in Some Airport Names? (& Some Funny Codes) |url=https://knaviation.net/x-in-airport-codes/ |access-date=2024-11-08 |website=KN Aviation |language=en-US}}</ref>

*[[Williston Basin International Airport|XWA]] for [[Williston, North Dakota|'''W'''illiston, North Dakot'''a''']], USA 
* [[Malmö Airport|MMX]] for [[Malmö|'''M'''al'''m'''ö]], Sweden
* [[Mora–Siljan Airport|MXX]] for [[Mora–Siljan Airport|'''M'''ora–Siljan Airport]], Sweden
* [[Dubai International Airport|DXB]] for [[Dubai International Airport|'''D'''u'''b'''ai]], United Arab Emirates (e.g. [[Dublin Airport|DUB]] was already allocated to [[Dublin Airport|'''Dub'''lin Airport]] in Ireland)<ref name=":0" /><ref>{{Cite web |date=5 Jun 2024 |title=Dubai International Airport (DXB) - Complete Guide |url=https://www.damacproperties.com/en/blog/dubai-international-airport-complete-guide: |website=Damac}}</ref>
* [[Milan Malpensa Airport|MXP]] for [[Milan Malpensa Airport|Milan '''M'''al'''p'''ensa]], Italy
* [[Federico García Lorca Granada Airport|GRX]] for [[Federico García Lorca Granada Airport|'''Gr'''anada International Airport]], Spain (e.g. GRA was already allocated to [[Gamarra Airport|'''G'''amar'''ra''' Airport]] in Colombia)<ref name=":0" />
* [[Gorom Gorom Airport|XGG]] for [[Gorom Gorom Airport|'''G'''orom '''G'''orom Airport]], Burkina Faso
* [[Birmingham Airport|BHX]] for [[Birmingham Airport|'''B'''irming'''h'''am Airport]], United Kingdom (e.g. [[Birmingham–Shuttlesworth International Airport|BHM]] was already allocated to [[Birmingham–Shuttlesworth International Airport|'''B'''irming'''h'''a'''m'''–Shuttlesworth Airport]] in the United States)<ref name=":0" />

Some airports in the United States retained their NWS ([[National Weather Service]]) codes and simply appended an X at the end. Examples include:
* [[Los Angeles International Airport|LAX]] for [[Los Angeles|'''L'''os '''A'''ngeles]]<ref>{{Cite web |title=LAX Official Site {{!}} FAQs |url=https://www.flylax.com/lax-frequently-asked-questions-faq |access-date=2024-11-08 |website=www.flylax.com}}</ref>
* [[Portland International Airport|PDX]] for [[Portland, Oregon|'''P'''ortlan'''d''']]
* [[Phoenix Sky Harbor International Airport|PHX]] for [[Phoenix, Arizona|'''Ph'''oenix]]<ref name="sky" /> (Note: the X does not originate from the x at the end of Phoenix but is the result of appending an X at the end of the NWS code.)