Technically, it was still remote-controlled - the ArduPilot Mega (autopilot they used) is a helper system, not a complete stand-alone autopilot. While it's capable of autonomous waypoint navigation and general independency from user input in flight, it requires that an R/C receiver is connected, and said receiver is at the very least used to arm the system and activate the autonomous controls. It can and probably did fly outside the R/C range, but I'm sure they had an option to use the manual controls as a backup from the chase helicopter, and they definitely did the landing in the end manually - I'm not even certain whether the plane firmware for the APM has an autoland function, and would be pretty impressed if it can land a bird that size so smoothly.