That's an excellent and very thorough answer that definitively settles the question -- thanks so much!
So much stuff in SW makes skyships seems like a present-day technology that I never got the impression that it was lost. Perhaps the player in question played in a game where it was treated as lost tech.
It's also possible that the player has skyships confused with the aircars that were produced by the lost civilizations from the Interregnum.
The simplest counter to the player's argument is that no matter how things were in games he / she has played in prior to this, in your game it's not a lost technology.