This is the second part of a two-part question. This part uses third-party worlds to illustrate a couple of points, but it is not in any way about them, therefore this question is not off-topic.
So in the previous part of this question was asking about the feasibility of an airship kept aloft by dragon fire breath. (Link here Dragon Sailing Airship Part I: Fire Air Balloon). Now I had looked over some of the other questions regarding airships on this site, and thanks to the sparse information I got from that question, I think I can safely eliminate hot air as a viable lift option. From what I can tell between the size the balloon would need to be, the limitation of fire breath, the wildly reduced cargo weight, it seems that the feasibility for that method of air travel was somewhere between “not possible” and “not worth the effort.” This part is going to deal with a bit of a more…exotic solution.
Who remembers The Hallelujah Mountains of Avatar?
Now according to the lore of the film, those floating mountains are initially ripped from the surface of Pandora thanks to the gravity of its gas giant parent and contain so much of a special room-temperature superconductor that electromagnetic magnetic currents are able to keep them airborne thanks to the Meissner Effect.
I started thinking if a room-temperature superconductor in a powerful enough magnetic field could hold up at least a hundred tons of rock and vegetation, why not an airship?
Then I thought it was so unbelievable that I was considering shelving the idea entirely, until I started listening to The Cartographer the Complete Series on audible, and learned that their airships worked similarly. The mechanics were different and explicitly magical in nature, but it was still magic rock mined from floating islands meaning that a bit more of a Sci-fi take on it might be worth it.
So the question is: How feasible is a large airship held aloft by Room Temperature Superconductor Anti-Ballast?
Note: I am using the term Anti-Ballast because the term Ballast describes heavy material, such as gravel, sand, iron, or lead, placed low in a vessel to improve its stability. The only antonyms I could find were to unload or empty which is clearly not happening here.
Edit: having looked over some of the questions that have been offered as answers to the question I can say none of them work as answers to this one. The one with the robot while using electromagnetism to remain airborne has nothing to do with what I am asking here. I am asking for the feasibility of this airship design, not asking how well it would fly if I crank up the juice which is what the robot is asking. I didn’t find it helpful nor worthy of the tittle Duplicate so please stop suggesting it. As for the floating city, I will grant there were a few concepts that helped a bit. Just a bit. But the primary defining feature of an airship is that it is mobile. Now while I thank you all for the additional reading material, sadly this question remains unanswered, so please don’t vote to close this question before it is even answered!
