So nice to see the Welsh use the French version instead of English.By the way, there is a book, written by a Dutch-Moroccan writer, named Paravion. The relative or friend (don't know who exactly anymore - but who is living in Maroc) of the main character (who lives in the Netherlands) thinks the main character lives in the country 'Paravion' because on all letters he receives, the name 'Par avion' is written :-)
I need to look for that book. Paravion is a place I'd like to live in!
The British one has Par Avion on it as a secondary line to Air Mail. It always has had in my lifetime but I don't know its origins.
The book is by Bouazza, Hafid. There doesn't seem to be an English language version but there is a Dutch one available on the web.
I'll wait for the translation, because Dutch... :)
I believe that the UPU regulations say all airmail labels must have 'Par Avion' in French, but that other local languages (like English) may be added as well. But maybe this has changed, as many European ones now say 'Priority'
In Morocco and Spain, it is "par avion". But usually they don't add labels. It seems the labels doesn't exist any more in the post offices (then, sometimes, they say they are "compulsory" fro international mail - ?!).
Thank you for coming. All your comments make me extremely happy.