For some people it stands for Visa Facilitation Service but for cognoscenti it's for the Vertical Flight Society and their database of practically six hundred separate projects around the world connected to electrical means of vertical flight. Between us we've called this latest outline the Mark V if only because I don't see another any time soon, what with it having ticked all my boxes the hard way.
It is actually listed as the Mark V (scale) as I don't want a proliferation of marques that would only confuse the public, if they not already confused enough by a dazzling array of projects worldwide. Once scaled up to adult proportions it will therefore be called the Mark V (beta) and thereafter and in fully-fledged form, simply the Mark V.
On one hand it's a naming convention I wish I'd thought of sooner, but on the other the V and IV marques of Spitfire were supposedly the best... so who's complaining?