I wouldn’t worry about that too much. First, there is no real evidence, that I’m aware of, of where this tech actually came from. I believe in Occam’s Razor when there is no evidence of anything accept that it exists, in this case I think it most probable that DARPA likely made a breakthrough in superconductivity and/or some kind of exotic material(s) to explain these crazy ‘aircraft’.
Second, a faithful belief that other more advanced space faring races exist, does not erase the fact that there is zero, absolute zero, evidence that any other beings, other than earthlings, exist anywhere outside of our tiny corner of the universe.
I’m just sayin, lets not put the cart before the horse. And just so you know where I stand on extra-terrestrials etc...etc... I’m open to them being real, I just need some kind of solid evidence before I can believe.
Oh I’m not concerned about it....just postulating a possibility.