What if aliens are the last remaining, most aggresive humans from the future?

I have this theory that aliens are nothing more than the last remaining humans from a very distant future. They are the most aggresive/sociopathic of humans and confiscated all technology and knowledge for themselves without realizing they did so on slowly dying planet. They look like little grey people because this is the result of the modifications required to maintain their lives with distant man made tech as well as to endure time travel.

Here's the dig. They have traveled back in time to "steal" back their current human forms because...well...their lives suck cuz they destroyed everything good in their future timeline. They can't land because of some sort of time loop issue so they are for the most part left "hovering" above the ground until they solve this problem, which has something to do with killing the soul in their earth body so they may then reinhabit it in this timeline and either hang around and raise hell or fly around in their new bodies or whatever. That's why they don't land and disclose themselves. All the abduction crap is just them locating, identifying, maintaining and preparing this timeline's body for rehabitation. Kinda like an organ farm except this is a human body farm.

This is just a small bit to stimulate conversation. I am curious as to what the readers think and how they may add to and improve this theory.