I'm pretty sure they were still on Krypton when her boyfriend was hanging on to the ledge...he fell so she jumped after him, of course it's just a dream but I think it was foreshadowing that the suit give them the ability to fly.
I have really enjoy Nolan's Batman films for what they were and Inception and many of his past films and I agree, his style is not what Superman needs. Superman is pure fantastical. But I do agree that the film needs to look like Superman landed in America, not some generic place and Snyder said that they strived to make it look like he landed in America and I love that.
And don't get me started on B&R...ugh. All that was was a damn toy commerical
No, Kara was not still in Krypton when she had the dream, she was sent out in outer space during her dream, where she was on a scouting trip to Earth until Dev-Em snuck in to wreck **** to smithereens (suggesting corruption within the Ruling Council, thus giving interesting backstory and legitimacy to Zod's concerns).
Plus, the location means nothing because of that Yellow Sun, you forget that Krypton does not have a Yellow Sun, so one cannot reasonably argue that the suit gave her the powers when Krypton has immensely dense gravity and thicker air than Earth. That means something else exists that allows her to achieve flight...which is of course, the Sun. Moreover, the Yellow Sun was referenced twice: One in her dream state, and one in reality, where she saw the Sun as she woke up. If that's not a clear indicator that the Sun is likely what gave rise to flight in the first place, I don't know what is.
By your logic, if the suit would've given Kara the power of flight, then she would've been designed in a suit of some sort (likely similar to what Kal-El is given), referencing her as not only Supergirl, but also one that has gained the ability to fly (her suit is the exact same as Zod's/Jor-El's in terms of texture and makeshift, but Zod can't even fly to save his life).
I honestly think you're jumping the gun a little bit in thinking that Nolan would do something like this to Kal-El. I trust Nolan, especially after saying that Batman =/= Superman, so ofc he's going to do something different.