With the number of planets out there, the chances that life exists off this planet is basically one. Intelligent life is also fairly likely.
That said, some lights in the sky don't mean shit to me. Even if I saw a "UFO", my first thoughts would be military to be honest. Until an actual being from another planet is sighted on earth I'm not buying it.
Don't get me started on conspiracy theories, I constantly argue with those retards and it never goes anywhere because they don't comprehend logic.