https://recordsearch.naa.gov.au/SearchNRetrieve/Interface/ViewImage.aspx?B=30030606
This entire document is worth reading.
Within this document we find commentary on Project Blue Book‘s (PBB) attempts to statistically analyze the performance characteristics of UFOs that were reported to PBB by firsthand UFO eyewitnesses. This was PBB’s estimate of the probability that UFO performance characteristics could be explained by then-known energy and propulsion technologies.
“Hence, assuming that no astronomical objects were left in the unknowns, the statistical tests were repeated with astronomical identifications removed. The odds were reduced to ten trillion trillion to one.”
Therefore, UFO performance characteristics could not be explained as being known energy and propulsion technologies back then, and they still cannot be today. Why? Because UFOs stem from a non-human intelligence having knowledge of energy and propulsion systems that we simply do not understand, or at least have not yet been admitted to the public today.