You're right about that particular video. But actually there were several articles and several videos. I only linked to the first one in the series.

These two will add more details- https://www.nytimes.com/2017/12/18/insider/secret-pentagon-u...

The second has the really spooky video. https://www.nytimes.com/2017/12/16/us/politics/pentagon-prog...

Around 27 seconds it starts rotating about one of its axes. Does not follow a fixed wing pattern, and it doesn't show any propulsion emissions on FLIR.