If I'm not mistaken, many years ago the three-letter IATA code for Chicago Municipal Airport on the SW side of the city used to be CHI. In 1949, Chicago Municipal was renamed Chicago Midway to honor the Battle of Midway and its IATA code was changed to MDW. Fair enough.
Meanwhile, in 1945, the Douglas Aircraft factory on the NW side of Chicago was closed down after WWII ended, and its associated airfield was given its historical name, Orchard Field, and the IATA code was ORD. In 1949, Orchard Field was renamed O'Hare Field to honor the famed WWII fighter pilot, Butch O'Hare. I've been unable to confirm if there's a specific reason why the IATA code was left at ORD despite renaming the airport. I realize that ORD didn't become Chicago's big main commercial airport for another ten years, so maybe ORD was determined to be "close enough" and it "didn't need" to be changed; however, does anyone know the real reason? Thank you!!
P.S.: I just noticed that Pal-Waukee Airport (PWK) at the northwest corner of Palatine Road and Milwaukee Avenue in north suburban Wheeling, IL, was re-named Chicago Executive Airport at some point, while the IATA code remains PWK. Maybe they simply just don't always change IATA codes when airport names undergo a change?

This webpage indicates the code was not changed to honor the airfields history.

IATA codes mostly do not change when the airport's name changes. The other code changes I know of are:

IDL->JFK
BAL->BWI

I can’t find the good blog post that talked history of many of the unusual airport codes that was from 10 or so years ago.

many airport codes are derived from old 2 letter codes like LA to LAX, PD to PDX.

in Canada the weather stations they had 2 letter codes. Canada had all the ones with airports at the time start with Y , the ones start with W.

names come from what was there originally MSY …the M is the person name and SY was stock yards iirc
MCI for mid continent
SDF standiford field
BNA berry field

leading Ns were reserved for navy/ military

The former was re-coded in 1963 and the latter in 1980

When Washington National was renamed for Reagan in 1998 it still retained its DCA code.

I guess it�s just to complicated to re-code an airport these days given how widespread and interconnected the codes have been embedded into various systems and the chances of something going wrong are just too great with incorrect bookings and so on.

Airports themselves might get a new name but their 3 letter code is now basically for ever..

I knew DCA as national before they renamed it and many locals only refer to it as National.

the way Reagan handles ATC strike he should not have been named after an airport

now there has been crap around naming Dulles after Trump

SNA got renamed for John Wayne.

Ah now you're talking about changing airport names rather then their IATA codes.

If they ever did rename Dulles to Trump it's very unlikely they would change the IATA code from DUL to DJT as that would generate significant international pushback not necessairly because of the name but because of the impact in the code.

The proposed Bill doesnt mention that. Though I note that not even the GOP reps in VA have signed up and nor have the uber trump sycophants like MTG who would normally be all over this sort of thing

https://www.congress.gov/bill/119th-...691/cosponsors

A little friendly prior restraint reminder. Let's please keep polarized political references isolated to Bad Omni. Thanks.

The current IATA code for Dulles is IAD.

MCI for Kansas City International is an interesting one because Mid-Continent was Wichita (ICT) before it was renamed Eisenhower.
Indeed, Dulles is IAD (there is no IATA code "DUL" -- even Duluth, MN, is DLH) and currently there is no airport coded DJT.
SNA (Santa Ana, CA) was renamed for John Wayne in 1979 with no effect on the airport's IATA code. Its previous name was Orange County Airport.
And thanks to all for the good info -- ORD was left unchanged in order to honor its historical name of Orchard Field. Fair enough.

In a similar vein is Burbank Airport ("BUR"). Since WWII it's been called: Burbank, Hollywood Burbank (current official moniker), Burbank Glendale Pasadena, Lockheed Air Terminal, and Bob Hope. AFAIK the IATA Code has always been "BUR".

i looked LEO is an unassigned airport code

I expect Chicago to rename one of their Airports after Pope Leo ( I�m thinking renaming O� hell might be a good idea)

I didn�t look�. DCX or DCB or DCI taken? DCA- national, DCB for Dulles as in A/B

I think the Dulles airport came because it was built for long distance and international flights thus IAD..instead odf DUL

From the IAD Wikipedia entry:

"Dulles originally used DIA � the initials of Dulles International Airport � as its airport code.[84] When handwritten, DIA was often misread as DCA � the code for Washington National Airport. This prompted officials to change Dulles Airport's code to IAD � standing for 'International Airport Dulles.'[84]"