I happen to know the daughter of an Air Force Colonel, who for 10 years was assigned to project blue book. We all know that blue book was an actual division of the Air Force, assembled to investigate UFO claims. Some say we still investigate even though the project was terminated decades ago.
Now, according to this woman, her father claimed that without disclosing top secret intel, that without any doubt and with 100% certainty, we have had visitors from other worlds here on earth.
A Colonel is just under a general. Which means he held a command position and was cleared with confidential information.
This testimony of course is not proof. But when told something with such conviction and certainty, and there's nothing to gain by disclosing this information? Well it leaves a skeptic like me, very close to convinced. After all, there are 200 billion solar systems in our galaxy, with 2 trillion galaxies in the universe. The odds of there being life out there? Billions to 1