Reasons to Believe that Aliens are exist

Alien dreams have always been powered by the desire for human importance in a vast. Most conspiracy theory is fueled by a desire to see the universe as ultimately intelligible.

Especially when it is started in a western nation.
The first reports of what could be called UFOs emerged in the late 1800s, though in those days they didn't use terms like "UFO" or "flying saucer," but instead "airships." 

UFO encounter occurred in 1897 Texas, when E.E. Haydon, a newspaper reporter for the Dallas Morning News, described an amazing encounter complete with a crashed spacecraft, dozens of eyewitnesses, a recovered dead Martian body, and metallic wreckage.

Another famous UFO sighting occurred near Phoenix, Arizona, in March 1997 when a series of bright lights were reported in the night skies.

October 13, 2010: UFOs over Manhattan turned out to be helium balloons that escaped from a party at a school in Mount Vernon.
 A Navy F-18 fighter jet filming a mysterious aircraft off the East Coast in 2015.

Here’s a video of a Navy Jet Encountering a UFO

INVESTIGATIONS:

UFOs are literally "unidentified flying objects,"  their origin is Russia, North Korea or the Andromeda Galaxy. The Air Force investigated thousands of unexplained aerial reports between 1947 and 1969, eventually concluding that most of the "UFO" sightings involved clouds, stars, optical illusions, conventional aircraft or spy planes. A small percentage remained unexplained because of a lack of information.

Much of the program and its conclusions have not been released, and it's not clear what if any useful information came from the effort. Several short videos of military jets encountering something they couldn't identify have been released by AATIP. 

 FINALLY, THE CONCLUSION IS

While it's possible that extraterrestrials in spacecraft exist and have visited Earth, the UFO sightings so far provide no real evidence. The lesson, as always, is that "unknown lights in the sky" is not the same as "extraterrestrial spacecraft."