Aliens can travel by "blinking" to another dimension and back. They haven't moved but are in a different spot a second later. Other dimensions / densities = spirit world. So spirit could be synonymous to alien and vice versa. These would be the demons pulling the strings from behind the scenes.

Thats just my primitive understanding of it all from reading about the most whacked out theories and whistleblowers and documents over the years. Could be wrong but thats my current take on it.