Quadrotor robot control is pretty good already and getting better quickly. You can buy these things off the shelf with GPS waypoint navigation. Completely autonomous. Not perfectly reliable in all conditions, but already usable on a calm day. Thus the control difficulty is not an issue in the medium term.
Many people have enjoyed the quadrotor videos from labs such as UPenn's GRASP lab. No one at the controls. Though the miniature flyers at Penn do use external localization and pre-computed trajectories, others are completely autonomous and react in real time.