Very frequently, yes.
It's been said that there have been UFOs and extraterrestrails since the beginning of time. Early visitors that helped build monuments, and basically start civilization. Since there have been people to see them, there have been UFOs.
Primetime Live - 1989 UFOs--- Seeing Is Believing was released on: USA: 19 September 2008
Peter Jennings Reporting UFOs - Seeing Is Believing - 2005 TV was released on: USA: 24 February 2005
There have been reports of sightings of white UFOs.
Hundreds of people have CLAIMED to have been abducted by UFOs, but many of the claims are obviously false and most of the rest have been of dubious veracity. There have been no positive evidence that any humans have been abducted from Earth by extra-terrestrial visitors. (But then, that's what "THEY" want us to believe!!)
UFOs have been reported in virtually all of the states at one time or another.
People have reported sightings of UFOs in France, but there is no proof of their existence.
The ones who study UFOs are called Ufologist. They study every thing about unidentified flying objects (UFOs).
There are none in existence. You can only find images that people claim to be aliens or UFOs. So far, there has never been any evidence to support their claims.
There are those among us who believe that UFOs have always been hovering nearby.
astrobiology
There is no credible evidence for this.