I assume you already know about how to film the person on a chromakey screen and key them out.
As for the background plate, ideally, you get a flying camera rig and use wires to actually move the camera down the building.
If you don’t have the budget for such a thing, you might consider building it in 3d.
If you don’t have the budget for that, you might be able to take some still photographs of the building and ground and build a fake 3d in After Effects.
If you can’t do that, you could just scale up a still picture from the roof looking down.
– The Great Szalam
(The ‘Great’ stands for ‘Not So Great, in fact, Extremely Humble’)
No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.