Thanks for the alternative derivation for "plane" which I had not seen before.
In the Wiki, they go a bit further and allow either the Latin planus or the Greek planos:
From the same source, this make a little more sense, IMHO.
"Aéroplane" originally referred just to the wing, as it is a plane moving through the air.[7] In an example of synecdoche, the word for the wing came to refer to the entire aircraft.