>> No, that is not true. Your own sentence use the word "most".

This is a non sequitur. The claim was "flying vehicle" is a valid translation for what is commonly translated as "flying chariot" in most cultures, i.e. non-Indian cultures. (It's certainly so for Ancient Egyptian myths, for which, unlike Ramayana, we have contemporaneous sources.)

I'm actually struggling to think of a culture which (a) had, at the very least, chariots or something like them and (b) couldn't have some part of its ancient mythology properly translated as "flying vehicle." Maybe Sumerian?

>> In Indian there is a distinction between vehicle("yaan") and chariot("rath").

Clarification: in modern Hindi.