Some of them are perfectly good witnesses, others are police or astronomers in groups who have watched them through binoculars, telescopes, and theodolites. Others are fighter pilots from any period, latest; Nimitz fighters. There have been mass sightings. The patterns of data around movements and maneuvers, shape colors etc., have been same from beginning. Patterns in data, etc. Then there are the civilian encounters...
RAND refused to release an important study on the existence of unidentified flying objects
Initially, we did refuse to release the UFO study, but not because it was classified or controversial. The paper was published in an internal series that was not releasable to the public because it had not been peer-reviewed. We eventually decided that the demand for the paper superseded our internal policy and posted it.
I'm not the only one to notice these things:
https://archive.org/details/TheCometaReport
UFOs: What To Do? 1967
George Kocher
Since World War II, there seems to have been a drastic increase in the number of UFO sightings. UFOs are unambiguously extraordinary and clearly inexplicable in modern terms. The author examines the UFO phenomenon and suggests the need for more standardized reporting to obtain more objective data.