I'm going to answer what these things are. Don't ask how I know - I just know for a fact.
They are just tourist vehicles from the future.
You pay to time travel back to the past to see whatever you want to see.
It could be for educational purposes, for elderly people to see their ancestors, people who want to look at certain animals and landscapes.
Unfortunately it isn't aliens.
There aren't any aliens and yes it's been confirmed there aren't any close by and it's fucking gay.
The vehicles just sometimes malfunction and lose their stealth abilities, but there's practically thousands of them all around you guys at any time.
You're probably going to be seeing them a lot soon because the Jewish extinction event is coming up and it's a major subject in future schooling.