Wernher von Braun knew the agenda:
The communist threat
The terrorist Islamist threat
The asteroid threat
and, finally, the alien invasion threat.
I heard of a variant. Friendly alien ships land in big cities and announce (in the local language) that they are willing to take an X number of citizens to a safe location in space, because this planet has become too dangerous due to chemical pollution. But the people the aliens are willing to take have to be good citizens and vaxxed and boostered at least 3 times. LOL