It's certainly used in English within the rest of the travel & tourism industry, and I supspect precisely because it isn't known as meaning "passenger", though that is its origin as you explain. It means "people we are catering too" whether in context that means a passenger, guest, occupant, diner, etc. and useful precisely to cover all those different cases. pax is a slang term for passengers, especially in transportation contexts. It is not a common word in general English and may be unfamiliar to some speakers. See examples and usage in comments. The term "pax" is short for " passenger " and is used to indicate an individual who is travelling or being serviced. Therefore, when you see "per pax" in a hotel or travel package, it means the price is quoted per person. PAX is a noun that can mean a tablet, a kiss, or peace. Learn the etymology, history, and usage of this word with examples and related terms.
