[EA-3167]

Probably done testing whatever it was, most likely some kind of tech for drones or maybe even the B-21 or F-47. Just like the "Flying triangles" from back in the 1980's and early 1990's were probably the F-117 and B-2 test articles.

[SnazzyUncle]

The stuff they showed on those videos a few years ago were a lot of the often balloons or children's birthday balloons and the incredible speeds were ~40mph.

There is several guys that on YouTube that seriously investigate the UFO sightings and almost all of them are either flares, children's balloons or in some cases people literally filming a reflection of a light fitting in a hotel room.