An aircraft is provided and includes a frame, drive elements configured to drive movements of the frame and a computer configured to receive mission planning and manual commands and to control operations of the drive elements to operate in a safe mode in which mission commands are accepted but manual commands are refused, a manual mode in which mission commands are refused but manual commands are accepted and an enroute mode. The computer is further configured to only allow mode transitions between the safe and manual modes and between the safe and enroute modes.