Pokemon Black 2 - Mistralton to Undella Town

Ok I seriously need help here I just beat skyla and seen the flashback and i know im suppose to ride a plane but where?! i went to celestial tower i got a call from my mother about stuff that i didn't really know since i was just mashing B and wasnt able to read so i continued to the toer Araragi was there nothing happened just talked and went to the bell and rang it == but nothing was there nothing happened and the elite 4 dude is blocking the way to twist montain soooo where am i suppose to go and where the heck is that stupid plane! :) thx

*Laughing a bit*
I did the same exact thing, no you simply go next door to the gym (the airplane place that previously had no use.) There will be a cutscene, then you will leave with Professor Juniper to a new location at the mountains near Undella bay.