First of all, I have to laugh at Squirtletamer08's post. Quite a few things wrong.
HGSS was a remake of possibly the best generation. The combining Kanto and Johto was an genius idea as it opened up more to do, more to see, and showed Kanto in a new light.
In terms of money, I think it'd bring more if they combined regions (albeit, not with Hoenn) because it gives more playability to the games rather than "Oh, I beat the E4. Not much else to do. Battle Frontier? Same thing...100%? Done. Now what...?".
You would have to be crazy to think that Gen 2 (Or specifically HGSS?) was the worst because they combined regions. As I've stated before, it was the best because it combined the original region most players, at the time of release, had become familiar with, as well as added a new region to venture through, keeping old tradition with new. Why anyone would want Hoenn, which was obviously a horrid reboot the the series, in a remake or combined with Isshu is beyond me, but I highly doubt it will happen.
On topic though, has anyone actually thought that maybe the plane is just there for decoration, or maybe it's like a normal building in that you can enter, do battles, and such without having to actually go somewhere? I mean, look back at Gen 1. The SS Anne didn't go anywhere, but it was relevant to the story as you couldn't continue the game without visiting (unless you traded a Pokemon with Cut). Heck, let's take this a step further and say its a Gym. I mean, why not? Every other theory I've seen on this forum is so Farfetch'd (Haha, pun), why not jump the shark and say it's where the Elite 4 is held! Or maybe the Battle Frontier!! Or maybe it's N--I'm sorry, ZOROARK'S hiding place.
Seriously though, speculation is fun, but jumping the shark is unneeded and quite pointless, especially when it's so absurd you KNOW it's not going to happen.
So in closing; I apologize if this offends anyone, but someone has to be sane, and I'm certainly not seeing it from anyone else.