It's been an ongoing debate I've had with some Aerial users, but I agree with you. Most if not all are real time or barely slowed down (latest beta I've put a slider to speed a video up/down partly to try and settle this).
They definitely are massively stabilised though and Apple used to update videos from time to time, tweaking stabilization, colors or sometimes length and pushing new versions. They haven't done that in a long while though.
Some seem shot from fairly high altitude and may use planes instead, and at least for some videos, I've heard they used 3rd parties to shoot them.
