Drones can't be operated over 400 feet (122 meters) but these Jets can be lower than 500 feet (152 meters) ?! https://www.facebook.com/video.php?v=1216056998575685 If there were to be a mid-air collision, guess who would be at fault...
In this case there would have been a NOTAMS, and it's up to drone operators to check for those. That's what they would say. It was the same with the helicopter/drone collision in New York I think. Normally it would have been ok, but the military helicopter was flying lower than normal but would have filed a NOTAM, see: https://www.notams.faa.gov/dinsQueryWeb/ Though, with a helicopter, it should be relatively easy to keep out of their way if you're flying within sight of your drone, where you should hear the helicopter coming, and see it quite easily, and be able to land. I think this is one of the reasons that DJI is being slow to release another drone, that they want to start including transponder technology so other aircraft can see them. If a drone with transponder had been flying in the above situation, which would be pretty dumb as everyone there was obviously waiting for the fly past, the pilots would have been alerted and aborted the display I guess?