I'm not sure much has changed in the FT days.;)

tks :)

Weather stations in North America used to have a two letter abbreviation. When some of those weather stations were outfitted with runways, in Canada they would add a "Y" before the code to mean, "Yes you can land here".

More details: http://www.skygod.com/asstd/abc.html

"X" roughly resembles the Greek letter chi, which is transliterated as "Ch". It's short for "christ". Originally the phonetic value was quite close to the modern English hard "k" sound, which makes more sense for representing "Christ", but chi has actually diverged in Modern Greek to be more like the "h" in "human".

Sounds like a trip for Port De Paix from Changuinola to Helsinki would be in order.:D

Much enlightening on both counts, Calchas ... thank you!

PAS, in the USAF, also means Personal Accounting Symbol, which is what's used as the accounting code for every person assigned to a specific unit on a specific AFB. Every unit on each base has its own PASCODE (with the first three letters signifying the base itself), and it's used to determine whom to bill for permanent change of station moves, temporary duty assignments, and other personnel-centered AF decisions that generate bills.

I have no idea how long PAS as its own code has existed. But if such a code existed in the Army Air Corps (or any military branch, for that matter) when commercial aviation was just beginning its boom, PAX may have stuck for "passenger" to avoid confusion with other acronyms, since both a Pax designation and a PASCODE can exist simultaneously on a set of orders - and then like a lot of military aviation speak, it translated over to the civvy side, as I'm sure most early commercial pilots were ex-military aviators who dragged familiar words and terms with them.

Just my two cents. I find etymology, even for the mundane, very interesting.

Perhaps for the same reason that the abbreviation for San Francisco is Frisco.

I think the 'X' was just easier to chisel into the original stone boarding passes than an "S" was.

haha oh go on,
I am a firm user of xmas, would only use Christmas if writing to a maiden aunt!

Oh and to add further fuel to the fire, the food company I used to work for used CHX for chicken

Presumably only for baby chickens though? :D

X is also the beginning letter of Χριστός , the Greek equivalent of Christ. Greek, you will recall is the language of the new testament. The usage is not new - it dates to the 16th century.

Why LAX is LAX...
 

Originally, when the US didn't have as many airports, the airports were identified with two character codes, so Los Angeles was "LA", Portland was "PD", etc. When the US had to go to 3-character airport identifiers, the "X" was added as a place marker that identifies the "Legacy" airports, so LA became LAX, and Portland became PDX.

LAS could not be the airport code for LA, because it is LOS Angeles. LOS is already in use by the airport in Lagos, Nigeria.

Passenger Experience, I believe. It's also tagged for the podcast of the same name.