[...horseless carriages, man made flying machines, and missions to the moon...]
...are all examples of things created by humans through a lot of hard work and ambition; they didn't fall on us from the sky by accident. But I get your point. It's a fact that there have been countless reports of stones falling from the sky dating back to antiquity, but scientists didn't accept that idea (and most openly ridiculed it) until perhaps a little over a century ago. Now, everyone accepts that stones fall from the sky as commonplace. Still, it took compelling evidence to bring about that widespread acceptance and there is no compelling evidence that supports the idea of aliens visiting Earth in spaceships.
I noticed that in retrospect. I thought afterward of the example of sea monster stories being mostly bogus, but the giant squid ones being true (albeit probably exaterated). But your rocks from the sky example works.
...and there is no compelling evidence that supports the idea of aliens visiting Earth in spaceships.
Don't tell Art Bell, but I agree there is no compelling collective evidence of this (i.e. verifiable to the public at large). However I do allow that there might be some private experience some individuals have that constitutes compelling personal evidence.