funny that Hyperspace is moaning about the Chitauri feeling 'weightless' when they were played by stuntmen in mocap suits as seen in set photos from the filming in NYC...
I "moan" because that's how it looked. They might well have done on-set mo-cap, but it sure doesn't look like it in most scenes. If they did, they did it poorly. They look like they should weigh close to 300 lbs, but they get thrown around like 50 lb anorectics.
And besides, most on-set photos did NOT feature stuntmen in mo-cap suits. That was what had people wondering for a long time who the villains would be - skrull duplicates of Avengers, or something else.