I'm fairly certain I've seen this video as well. I've wondered why it hadn't been shown more, but thought that perhaps it was identified. I can't say where I've seen it, but on some documentary. I didn't think it was that rare, but must be and I haven't seen it often. And I don't even remember it being specifically associate with Phoenix, but maybe it was. It seems I was watching some segment on Black Triangles when I saw it.
Anyway, if it is the same video, it is a curved, dark, shadowy, craft that moves from right to left. Not a great speed. The camera follows it for a few seconds and I think thats it. You can see what I guess would be the "boomerang" shape. It doesn't give me the sense of being that large, but would be hard to tell. Seemed, maybe closer than a normal aircraft and what I remember an array of white lights.