Editing IATA airport code (section)

====United States====
Since the [[U.S. Navy]] reserved "N" codes, and to prevent confusion with [[Federal Communications Commission]] [[Call signs in North America|broadcast call signs]], which begin with "W" or "K", the airports of certain U.S. cities whose name begins with one of these letters had to adopt "irregular" airport codes:
* [[Newark Liberty International Airport|EWR]] for [[Newark, New Jersey]]
* [[Tweed New Haven Airport|HVN]] for [[New Haven, Connecticut]]
* [[Norfolk International Airport|ORF]] for [[Norfolk, Virginia]]
* [[Key West International Airport|EYW]] for [[Key West|Key West, Florida]]
* [[Nome Airport|OME]] for [[Nome, Alaska]]
* [[Nashville International Airport|BNA]] for [[Nashville, Tennessee]] (whose airport's original name was ''Berry Field'')
* [[Napa County Airport|APC]] for [[Napa, California]].<ref name=sky/>
* [[Wilmington International Airport|ILM]] for [[Wilmington, North Carolina]]

This practice is not followed outside the United States:
* [[Karachi]] is [[Jinnah International Airport|KHI]]
* [[Warsaw]] is [[Warsaw Chopin Airport|WAW]]
* [[Nagoya]] is [[Chubu Centrair International Airport|NGO]]

In addition, since [[Q code|three letter codes starting with Q]] are widely used in radio communication, cities whose name begins with "Q" also had to find alternate codes, as in the case of:{{citation needed|date=August 2020}}
* [[Qiqihar]] ([[Qiqihar Sanjiazi Airport|NDG]])
* [[Quetta]] ([[Quetta International Airport|UET]])
* [[Quito]] ([[Mariscal Sucre International Airport|UIO]])
* [[Quimper]] ([[Quimper–Cornouaille Airport|UIP]])

Even this practice is not followed universally. For instance [[Owerri]] in Nigeria uses the code [[QOW]].
IATA codes should not be confused with the [[Location identifier#FAA identifier|FAA identifiers]] of U.S. airports. Most FAA identifiers agree with the corresponding IATA codes, but some do not, such as [[Saipan International Airport|Saipan]], whose FAA identifier is GSN and its IATA code is SPN, and some coincide with IATA codes of non-U.S. airports.{{citation needed|date=August 2020}}