In my opinion, the universe is too big for our planet to be the only one with sentient life. Heck, even our own planet is apparently too big for humanity to be the only sentient life. The laws of physics, though, seem to preclude the routine visitation of our planet by those from other systems and galaxies--especially in the manner so often claimed.
I’ve always been curious, though, about the kind of hyper-intelligent, super-advanced, trans-galactic species that would develop such technology just to "covertly" visit our planet, fly around poorly, and shove things up the asses of folks in flyover states.