And the answer isn't going to be any angels or gods.
You sound very certain.
Pray tell, where is your irrefutable evidence to back up these claims?
Your prior statement of crimes charged by the Church is historic fact. This happened. But aliens? Who knows. Are they angels? I doubt this, and I quote Arthur C. Clarke's third law:
Any sufficiently advanced technology is indistinguishable from magic.
Which holds quite a bit of truth. What Christ did in the Bible seems impossible. Beyond belief. Incapable of comprehension. UFOs, on the other hand, while flying craft, are still mechanical flying craft. We can do a lot with machines. But can a simple man walk on water, or create food from nothing, or heal the sick or even... rise from the dead?
So myself, I think they're separate. As a counter-point to those saying UFOs are angels--or others who think they can't exist because they are never mentioned in the texts--the Bible is the book of Earth and nothing more. It was written in language understandable and interpretable to humans living at the time. Impossibilities were exaggerated or allegory and metaphor was used, because if you put a VR helmet on a peasant from 1000 BC, they'd likely think you are a god, too. I think if UFOs and aliens exist, then... they're UFOs and aliens.
As Christ demonstrated, he needed no machines to accomplish what he did--no vehicles, no devices, nothing but himself--hence Clarke's third law. So the notion an angel would need a machine, too, simply doesn't jive with what is written.
That's my opinion.
If any mortal did encounter God, or an angel, they'd think they were magical, too. But a creator of the Universe has an advantage the rest of us don't: They created a Universe they don't reside in. Just like a child playing in a sandbox. The child visits the sandbox, maybe even builds the box, pours the sand in, then shapes the castles, tunnels, villages and more. When they leave for the night, though, things change due to external forces the child does not control. The box reacts to the environment it is in, until the child manipulates the sand again. But they don't live there, they visit.
None of us can prove the existence of God, because a perfect sandbox would be built in a way that the sand could never leave the box, but would be confined. Besides, leaving the box would invalidate the experiment. So build a perfect box, keep the subjects inside and watch what happens. Likewise, none of has been able to prove where life originated, either. We can't. We've tried. But we've never come close cells spontaneously forming from nothing, then fabricating their own instruction set and self-replicating those instructions.
So we can't prove one side of the argument, and we can't prove the other.
Does that mean we should hate one another, because we disagree with opposing views? Nah. My take is we should share these views without falling into the traps of absolutes. Or hate. Entertain various views but enjoy how much better this world is for having variety, rather than everything being the same.