On the back of the Vulture there's a thing with wings that almost looks like a little drone. Is that actually a drone, what purpose does it serve, or can it detach and fly around?

It's just a design detail. I guess it would be perceived as some sort of scanning equipment, essentially. But there's nothing as exciting as detaching and you flying it around and scouting, or having a mini Vulture, a baby Vulture, just detach. No, there's none of that, sorry.