What is the etymology of the term “pax”, the commonly used shorthand in the airline industry for “passengers”?

That’s all lizban wanted to know – nothing more, nothing less.

But NOOOOOOO, FlyerTalkers couldn’t just answer this seemingly simple question and leave it at that. Nope, they have to go and fill our heads with a bunch of fascinating history about a whole host of airline-industry abbreviation oddities.

Such as, why do so many airport codes end in an “X”?

That’s because when they moved from two letter to three letter airport codes, some airports just added an X where there wasn’t a logical third letter.

 

If Los Angeles’ 2 letter code had been LO, the new code might have been LOS, but since it was LA they chose to add an X. Same thing happened to Portland, which was using first and last letter (PD to PDX) and to Phoenix (PH to PHX). ~YEGTigger

Why do many Canadian airport codes begin with a “Y”?

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”. ~Calchas

And in the spirit of the season, You want to go where? gives us some insight into the use of “X” to replace “Christ” in Christmas:

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.

All of this isn’t to say that the discussion doesn’t delve into the reasons for the pax abbreviation. In fact, there are several interesting bits and pieces to that particular puzzle, but you are going to have to click through to get the good stuff.

Read this terrifically entertaining IBB thread in its entirety: Why is is PAX not PAS?