I don't think ET interventions happened like beings in spaceships landing on earth. Like mankind is trying to conquer the universe using spacecraft. Kids stuff. While there are other ways to do this, change dimensions or something,maybe just transform. In a lot of cases, people wearing the outfit suggesting outer space travel,these beings possibly were visitors from another continent. Inka Enki...lol
Its like when we are long gone, they dig up space-invaders and star-trek stuff, and they say hey these guys were pretty busy out there, and oh have you checked out all these planets on the U.S flag." They must have come from all over the uni-verse...( Europe is on its way too.) LOL
Oops forgot Superman and Zorro...flying gods...