Also, I will bring up Pirates working under the Librarium. It's entirely possible.
But you're not a Pirate, if you have a Letter of Marque from the government saying you can legally seize other ships and their contents. You're a Privateer~
Are wyverns and such going to be more common as well? I'm digging the idea of an aerial cavalry~
Since we have airships, I dont think it would be a stretch for navigators to keep good records about winds currents and common weather conditions. Maybe something like multi layered map or an almanac. If certain winds flow cosistently in one direction or another, then you could have glider ferries or aerial highways for glider traffic.
Also if these ships are held aloft by magic, what's powering the magic? Are there any measures taken to protect it?
This strong Skies of Arcadia vibe reminds me of moonfish.
Edit; Also, I would expect that flight, either natural or magical, would be commonplace if floating landmasses are a frequent occurrence. Or at least something to mitigate the dangers of falling to one's death. Perhaps, there are mass-produced magic items for this?