In my opinion the extraterrestrial hypothesis remains plausible as the explanation for the major category of UFO-related phenomena, vehicle sightings especially with optical media, radar and EMI interaction.
Some of the theoretical arguments against the extraterrestrial hypothesis (ETH) for UFOs are that there is zero knowledge of other life much less other intelligent life, if it actually exists it is apparently impossible for it to get here, the apparent ridiculousness and absurdity of some of the phenomena (such as alien abductions, many UFOnaut encounter accounts, brilliant “advertising” lights), the supposed parapsychological connection, and the supposed similarities with historical accounts of things like fairy sightings.
But as far as I am concerned real data, evidence, always trumps theory. These following cases and many others of the same sort were real events in the world, in space-time, occurring to real people that presented as described. Their testimony and other evidence can’t reasonably be dismissed just because they appear fantastic or theoretically preposterous. Especially with good observers like pilots and police officers (sometimes multiple) whose testimony would otherwise be accepted in a court of law. The burden is on the skeptic to credibly demonstrate how these cases are actually misperceptions, hallucinations, errors, hoaxes, useless anecdotes, etc. And on the skeptic of the ETH to come up with a more credible general explanation for the many cases of physical interaction with physical apparent vehicles.
Some people have observed strange apparently structured material objects in the atmosphere that give the strong impression of being vehicles, somebody else's hardware.
The best cases stand on their own merits as evidence that on some rare occasions what seem to be alien vehicles appear to humans, sometimes producing physical effects including radar returns, radio interference, ground traces and leaving images preserved on photographic film or electronic media.
For a detailed summary scientific review and analysis of the various types of physical evidence related to UFOs, there was the Sturrock panel report, see
https://ufoscoop.com/physical-evidence-related-to-ufos/.
The relatively recent (in 2004 and 2015) sightings and radar trackings of small UFOs shadowing US Navy carrier battle groups, featuring multiple pilot and ship radar reports and HUD video display recordings amount to some of the best data. Some of these HUD videos were released by the Defense Department a few months ago.
Just a sampling of some of the better older data:
– The 1947 Kenneth Arnold sighting
Except for the WWII “foo fighters”, this begins the modern era of UFOs. A good analysis is at
http://www.martinshough.com/aerialphenom...lysis2.pdf . There do not seem to be any valid optical, geometric, geographical, psychological or other reasons to doubt the major features of Arnold’s sighting as reported and they are internally consistent. The analysis results in a range of 16-20 miles, a minimum length of 70-90 feet, and a speed of 890 to 1200 mph. Arnold described the objects as trimmed-off in the rear thin shiny “saucer-like” discoids reflecting sunlight blindingly like metal at certain angles.
– The Chiles-Whitted Case – Montgomery, Alabama, United States – July 24, 1948
– The Nash-Fortenberry Sighting (aircraft encounter with formation of UFOs) – Virginia, United States – July 14, 1952
– The RB-47 UFO Encounter – Gulf Coast Area, United States – July 17, 1957
– Socorro / Zamora UFO Incident – Socorro, New Mexico, United States – April 24, 1964
– Coyne Helicopter Incident – Mansfield, Ohio, United States – October 18, 1973
– “Dogfight over Tehran”, the 1976 Iranian Air Force Incident, a multiple pilot/ground/radar/visual/EMI signal case. Details at
http://www.nicap.org/760919tehran_dir.htm .
– The Cash-Landrum Case – Huffman, Texas, United States – December 29, 1980
– Japan Air Lines Flight 1628 Over Alaska – Alaska, United States – November 17, 1986
– Belgium Triangle UFO Sightings – Belgium – October, 1989
– Illinois Triangle UFO Sighting (by multiple police officers) – Illinois, United States – January 5, 2000
The 1999 French Cometa committee report, summarized at
https://www.ufocasebook.com/cometamain.html . This was an in-depth study of UFOs, covering many aspects of the subject, especially questions of national defense. The study was done over several years by an independent group at the Institute of Advanced Studies for National Defense, or IHEDN, and by other qualified experts from various fields. They took the extraterrestrial hypothesis very seriously when considering the many of the best French cases.
For an exhaustive analysis of electromagnetic effects generated by UFOs, see Fifty-Six Aircraft Pilot Sightings Involving E-M Effects – Haines (1992), at
http://www.nicap.org/papers/92apsiee.htm .
My view is that this phenomenon is complicated, being composed of several different types of phenomena of fundamentally different natures that interact in various ways. Other explanations than the ETH, some involving paranormal phenomena, subconscious influences of the Zeitgeist, extra-dimensional or time travelling aliens, etc. etc. may possibly apply to other subcategories of UFO-related experiences including alien abductions. I think both the modern “zeitgeist” and accounts of real physical alien vehicle encounters could stimulate subconsciously generated fantasies like alien abductions and subconsciously generated fantastic or apparently ridiculous “occupant” encounters (like the Betty and Barney Hill case).
The phenomenon is probably composed of many different components and levels. So as to the question of which potential explanation is the real nature of the UFO phenomenon, it is probable that the question is simplistic and that the answer is “all of the above”.
The final observation is that this phenomenon involves a quintessential cognitive dissonance, that simply can’t be resolved at our level of knowledge and wisdom. This is reminiscent of the cognitive dissonance involved in the reductive materialism versus spiritual reality debate; in this latter case there is also a strong body of evidence on both sides.