5 Things I Didn’t Know About Airport Codes

On the most recent episode of the always-excellent “Airlines Confidential” podcast journalist Seth Kaplan and former Spirit Airlines CEO Ben Baldanza were talking about airport codes and they shared several things I wasn’t aware of, though perhaps have heard in passing before.

  1. Airport codes beginning with N are reserved for naval air stations (so “Newark is EWR”) Seth Kaplan says Akron, Ohio – home to the football hall of fan – therefore cannot be ‘NFL’.

  2. Codes beginning with W and K are reserved to avoid confusion with radio stations which is why MCI – Kansas City International – isn’t KCI (but local media refers to it frequently as KCI)

  3. Some airports kept National Weather Service codes when moving to 3 letter codes, and added an X (PDX, LAX, PHX)

  4. Two airports within the same region cannot have the same first and second, or second and third letters. The idea is to avoid confusion between DCA and IAD, IAH and HOU, DFW and DAL, etc.

  5. The FAA has 3 letter codes that are usually the same as IATA codes, but in the case of Phpenix Mesa Gateway the IATA code is AZA but that’s not what the FAA uses. The FAA code, used for general aviation, is IWA.

While it’s difficult to change an airport code, not only complying with the rules above but also making sure the code isn’t taken, it’s something that’s certainly been done. For instance Idlewild (IDL) became JFK.

However when Fresno Air Terminal (FAT) changed its name to Fresno Yosemite International, to market the airport as a gateway to Yosemite National Park, they were unsuccessful in getting their code changed to FYI. They can call themselves FYI if they wish, of course, even if it’s not used officially.

Denver (DEN) isn’t DIA, but local media refers to it as DIA. Ben Baldanza suggests though that at one point the new airport was going to use DIA rather than transferring DEN from Stapleton, which was decommissioned as a commercial airport. Why on earth I sometimes see Orlando news media referring to ‘MCO’ as OIA though I do not know.

Talking about Baltimore airport changing its code from BAL to BWI in 1980, former Spirit Airlines CEO asks “I wonder what Bewani is now and I wonder if they had to bribe ’em in any way, if Baltimore had to pay ’em something, how they get them to take another code.”

bwi airport
Credit: BWI Airport

As it turns out I’ve answered that question.

  • When Baltimore remained itself Baltimore Washington International they wanted the code BWI, but it was already taken by the airport in Bewani, Papua New Guinea.

  • However when Air Niugini wanted to fly to Hawaii the US government demanded the airport code in exchange for the route authority.

  • Air Niugini no longer offers Honolulu service, while Bewani Airport – 608 miles Northwest of Port Moresby – remains BWP.

About Gary Leff

Gary Leff is one of the foremost experts in the field of miles, points, and frequent business travel - a topic he has covered since 2002. Co-founder of frequent flyer community InsideFlyer.com, emcee of the Freddie Awards, and named one of the "World's Top Travel Experts" by Conde' Nast Traveler (2010-Present) Gary has been a guest on most major news media, profiled in several top print publications, and published broadly on the topic of consumer loyalty. More About Gary »

More articles by Gary Leff »



  1. @Colin:. The Key West example belongs in paragraph 2. They must’ve been a single item that got split into two during editing (and I use the term “editing” loosely).

  2. Should also retitle this “US Airport Codes”, as there are many international airports which violate these US rules (KUL for Kuala Lumpur, for example)…

  3. Millington NAS code was NQA. When the airfield changed from Navy to civil and became Millington-Memphis Airport the code remained NQA by the airport”s request.
    For all large airports in the lower 48 states, for flying purposes, their code begins with K–KNQA.

  4. Orlando International Airport (OIA) is what the local government funds, hence news reports referencing that name. ORL is the executive airport closer in to the city.

  5. Millington NAS code was NQA. When the airfield changed from Navy to civil and was renamed Millington-Memphis Airport the code remained NQA at the airport’s request.
    All large airports in the lower 48 states, for flying purposes, have as the first letter of their code K– KNQA.

  6. Regarding #2, there are a few commercial airports in the US using codes starting with K and W.

    KOA Kona, Hawaii
    KTN Ketchikan, Alaska

    WRG Wrangell, Alaska
    WST Westerly, Rhode Island
    WYS West Yellowstone, Montana

  7. @Doubletree and Gary: The commercial airport serving the Pro Football Hall of Fame Is Akron-Canton Airport (CAK). It’s served by United Express, American Eagle, Delta Connection and Spirit.

  8. 1 more interesting thing about airport codes: Canadian city codes all begin with a Y.
    Calgary YYC
    Toronto YYZ
    Vancouver YVR
    Montreal YUL
    Saskatoon YXE
    Winnipeg YWG
    Ottawa YOW

  9. Kansas City International is MCI because it was MidContinent International airport before the city moved commercial airlines from the downtown airport (MKC) to the present location. Prior to commercial service moving to MCI, it was primarily used as a maintenance facility for TWA.

  10. @mdtravel “Lots of typos Gary.”

    Are they material? Were you misled?

    If it’s an issue for you, perhaps you should demand a FULL refund. Or just chill.

    IOW, I don’t even get the reason for comments like this. You took the time to post something so shallow and small. To a blog you peruse for free.,

  11. The K and W restrictions I think date from the time decades and decades ago when airplanes sometimes used commercial AM radio stations as low frequency navigational aids.

  12. The number of people living here in Orlando who know why the code for Orlando International Airport is MCO gets smaller each year. As someone else mentioned that land/facility used to be McCoy Air Force Base. The base no longer exists but the name lives on in a few places here… McCoy Federal Credit Union. Most of the media refer to the airport using OIA (the official name for the airport is Orlando International Airport) even though all those vowels don’t really flow off your tongue.

  13. @Gary Leff
    The Pro Football Hall of Fame is in CANTON!!!! The NFL was founded in a garage in Canton, the Hall of Fame is near the intersection of Rt.62 and I-77 in CANTON!!!

  14. The most useful airport code in the country is DCA because it allows us to avoid the issue of the unwanted name change.

  15. @Charlie – I still call it National airport not out of political objection but because I moved to DC long before the official name was changed

Comments are closed.