While this video is somewhat sort, it still gives some good information!
First thing's the flying. We see what it's like heading into the overworld. There seems to be a light that comes from the area above of where you drop down. Probably there to make sure you don't get lost, in case you want to explore.
Then when you land. A parachute doesn't seem like a bad idea. I always thought Phi would be an assistant in helping you land, but this works too. =D
I also see a statue when you land on the ground, that looks familiar. I'm wondering that either those statues are there either for saves, OR, since they look like birds, may be points where you can call your bird. Then again one was found in a temple...
And Eldin Volcano. Makes me wonder if the light spirits will play a role in the story as well. Maybe we'll see the Gorons here, but I doubt it. I think instead we'll see one of the new races, the Mogmas. They were shown before in some kind of rocky environment. Maybe this is the place.
Edit:
I'm already in love with Phi's voice. The effect is very nice. Very un-earthly. Anywho, the location is...interesting. Eldin is an odd place for a volcano. As far as I can remember, it's a foresty region. o-o But time does change things, and in saying that, I guess SS is more further back than I originally thought. :O
Eldin was where Karariko and Death Mountain were in TP. It was somewhat barren. I think you're thinking of Faron. That was the foresty place.