I've seen people link the fact that the new Unova shows an airplane in Mistralton City and that you can go to other regions. They only added that airplane because there actually was an airplane in BW, however it was never shown on the map. If you look at the new Castelia City, you will notice they have now included boats. This means they only added the airplane because it wasn't included on the old map, along with the boats in Castelia.
Just trying to put to rest any stupid Hoenn speculation. I swear if that isn't the worst type of speculation. Just wait for your R/S remakes instead of speculating over a silly inclusion like Kanto in G/S - pointless and neglected.