At a couple of points it flies in a way that would be in front of people if it were low. They don't react. Maybe it's dark, or maybe it's an indication it's high up
Looks like the slant range is 3.5KM. Slant angle seems, very roughly, about 30°, putting the aircraft at 1.75KM, or around 5-6000 feet.
So this could easily be some balloons 2,000 - 3,000 feet above the ground. With a strong parallax effect.