This is SAMARAI, a UAV that Lockheed Martin has been working on based on a monocopter platform. A monocopter is like a helicopter, except that the entire vehicle consists of a single rotating airfoil, making them somewhat impractical for manned flight. And, from the looks of things, more than a little dangerous, although the project was named SAMARAI not after its efficiency at decapitations but after samara, which are those monocopter seed pod things that fly down off of trees.
Eventually, the SAMARAI project was supposed to produce a nanomonocopter (?) about the same size as a seed pod (on the order of 1.5 inches long and 10 grams in weight), driven by a miniature rocket or jet thruster, able to send back streaming video (that was stabilized somehow), autonavigate, and deliver a 2 gram payload up to a kilometer away. The big version in the video above was a testbed to help engineers figure out just how to get this thing to fly in a stable and controllable manner.
Now, I’m not entirely sure what’s going on with this particular project… According to Danger Room, the SAMARAI project was canceled last year after completing phase 1 of a DARPA nano air vehicle contract. Phase 2 of that contract, incidentally, went to AeroVironment for this. The information included with the above video, however, suggests that this flight test is “recent,” and while no sources are cited, the YouTube channel it’s from is run by an editor over at Aviation Week (or so it says), so there’s some amount of credibility there. Maybe we’ll get some answers in the near future now that this video is live.