What about this idea? DoL and DoH in the linkshell work together to build the airship, that the LS can use as their linkshell house. The airships can be fully operated and navigable, just like in any other FF games. There would be some services offered inside the airship, as the airship gets upgraded. For example like resting bonus, NPC that grants buffs, NPC that sells special crafting items.
Now we have anima and chocobo, you may ask, what is the airship for if you can teleport? But I say that the main purpose for the airship is to serve as linkshell house, and for gathering among your LS mates. The airship can start out small, but as they get upgraded, more rooms become accessible and can be decorated. There can be an open deck so people can go outside while it is flying. There can be a bar inside, crafting area, etc.
One of the major problems that can arise is that cities will become deserted as everyone who is part of a linkshell just stays in their airships. But perhaps some services like an Auction House should never be accessible from the airships, so this will force people to go into the cities. The airship can also run on fuels, so once in a while they have to dock at one of the major cities for a day or two (LL, Uldah, Gridania).
Also, floating city like this picture below, can only be accessible by the linkshell airships. The airships can dock here, and the city can serve as a PvP platform in the sky! For those that want to PvP, Linkshell vs. Linkshell, they can go onto one of these floating platforms to do so. There would probably be other floating dungeons that can only be reached by the LS airship, to be completed together with your LSmates.
I’m still thinking on how the linkshell members can board the airship once it is flying in the sky. It would be annoying for the pilot to have to land the airship everytime someone wants to board/deboard. Maybe there can be a aetherite to beam into the ship. And as the airship gets upgrated, it can beam players to various aetherites around the world, once they have been discovered, and for a cost.
What do you think?