I've seen a tent do that before.
Also saw one with a friend, wife and kid float past me in ours when a massive rainstorm hit. They didn't stake theirs down. We just sat in a foot of water most of the night.
Don't get on that ship! The book, "To Serve Man" it's a cookbook!
Classic Twilight Zone.
Well done on the quick research showing it's a balloon.
Everything is fake until proven to be real.
Guilty until proven innocent.
Keep watching the skies for rogue tents.
An actual invasion would probably be an invisible poison to clear out the humans.