Re: What happens when the drone is out of range of the device?
Drones will have accelerometers and compasses and could continue on their path using Dead Reckoning in lieu of a GPS fix. It'll then correct itself once it gets GPS back.
To return to the operator, some drones will just repeat all the commands they were issued since takeoff, but reverse them. It may not get them back to exactly where they started, but at least pretty close.