Yesterday, while I was on my private server, I discovered how flight paths/pathing works. The way the gryphon/wyverin flies really has nothing to do with where the flight master is.
In a flight with no places in the middle (EG stormwind to westfall) there are 2 steps. The first one is when you actually get on the mount, if flies you a little bit to the exact location of the SW coord, and then it goes on it's flight and lands at westfall's coord. But, if you spawned ANY flightmaster (not just the stormwind one) in stormwind, it would still give you all your options and if you went again to westfall, it would fly you through walls and stuff to get to stormwind's coord first, and then it would go as normal to westfall.
Maybe you all knew that, and I just am an idiot, maybe not.
I know there used to be a way to get to GM island on live servers through editing where zeppelins go, so obviously it was client side. Maybe you could do something similar with FP's?
EDIT: this means that there is nothing inherently DIFFERENT with flightmasters, other than a tag saying it's a gryphon master, or wyverin master.