Some people may believe that UAVs or their control systems are still inherently unreliable or do not have the full functionality required for complete flights. This is however demonstrably untrue, . . ."
This had previously been hashed over in a previous thread.
Keep in mind that UAVs are operated by the military and are funded by unlimited tax dollars. That's one of the reasons the government keeps the NUMBER of UAVs that have NOT returned to base a secret. In fact, hundreds have been lost, and not just in combat.
Just as the automatics in an airliner . . . everything works OK until something breaks, except that in a UAV the remote operator may lose control when the autopilot goes on vacation, or when the hydraulic system springs a leak..