I doubt he could have seen any drone. They fly too high, are too small, too quiet, and was nighttime. Maybe he was tipped off by the Paki gov't...or maybe he was scattered about the area.
The use of drones, as well as the all mighty satellite, to protect us from those who want to do us harm lead directly to 9.11. As long as the CIA takes the easy way out, and doesn't get more folks in on the ground, the bad guys will have a much easier time of operating.