?? That sounds pretty crazy to me. (Would be very cool though.) Any mistake and you'll lose your plane on the street or on any other roof which would be completely inaccessible. If I flew little drones I would try it off my roof - IF I had roof access, and there isn't access in this building. Roof access isn't common. I can get on the roof @ my office building but I'll be darned if I'm gonna go lose a plane off the roof!