I don't even know where we go from here, to be honest. Grusch's testimony (that he requested and was denied access to these SAPs) probably rules out overhearing rumours and probably rules out accidentally blowing the whistle on disinformation campaigns. Grusch is either knowingly complicit in a highly sophisticated, convoluted and frighteningly bold disinformation campaign himself, was specifically targeted by a disinformation campaign designed to disseminate this information in approximately this manner, or he's telling the truth as he knows it, crash retrieval SAPs exist, and disinformation campaigns have been used to reinforce the UFO taboo and conceal the programs.

I suppose highly motivated reasoning from a true believer would be another possibility, but the specificity of his answers makes this unlikely. Lying for profit, status or similar motives seems unlikely given his credentials, clearances and career, although I could see him being persuaded by others in that circle to exaggerate to kick up a hornet's nest and progress the issue. Wild.

They might be busy updating on Grusch's statements that he knows the names of the crash retrieval SAPs, the individuals involved, the companies involved, the locations involved and the tradecraft of how these programs have been hidden from oversight and is willing to reveal these details in a closed SCIF. (Reciting off memory as I watch the hearing, here; that is my overall impression of his answers and almost certainly the impression he wanted to create, but his exact wording might have been a little different.)

Thanks! Very much agreed re. psyops, particularly given the context of the Cold War. (American IC actors were initially concerned that UFOs were Soviet psyops or secret technology, while Soviet IC actors were initially concerned that UFOs were American psyops or secret technology.)

I hesitated to use the term strawman, but yes, that's exactly it. I don't think skeptics are intentionally attacking a strawman; they just aren't remotely familiar with the subject, so are attacking what they think UFO proponents actually think without realising that there are good reasons why sober and serious thinkers (Hanson, Hynek, Vallee) who overcome the stigma to actually examine the evidence end up tanking complexity penalties to generate pretty out-there-sounding hypotheses to explain the bafflingly compelling (relative to ghosts, Bigfoot etc) data.

Yes, I didn't structure that part very well. My general point was that evidence is accumulating in the direction of Mars having had life during the Noachian period. Not a strong signal (as the evidence isn't there yet), but a weak signal in favour of the stellar nursery model alongside strong evidence for molecular panspermia. You are quite right that a habitable but uninhabited Mars would be weak evidence against panspermia.

The suggestion isn't exactly ball lightning, but similar classes of phenomenon (including things like the well-attested Hessdalen lights), possibly triggered by seismological activity and meteorite activity. The hallucination aspect is based on modulated magnetic fields allegedly producing abduction-like psychedelic experiences in Canadian medical studies.

I agree this explanation doesn't account for USOs (including the infamous Nimitz UAP, which was allegedly recorded travelling underwater at implausible speeds via sonar), physical trace evidence of alleged UAP landings (e.g. the Zamora case), and other aspects, and seems like an attempt at rationalising away awkward evidence for exotic (read: extraterrestrial) UAP. Nonetheless, natural atmospheric plasma phenomena do represent a plausible explanation for many UAP, particularly atmospheric lights performing instantaneous accelerations and other erratic maneuvers. Metallic appearances can't be ruled out, either; there are reports of metallic and opaque/black ball lightning.

A few unorganised thoughts:

1. The extraterrestrial hypothesis is unfairly dismissed (among rationalists and skeptics) due to unjustifiably low priors on alien visitation/presence/proximity and excessive confidence in this ontology, preventing appropriate updating around confusing evidence to the contrary and encouraging motivated reasoning around reflexive debunking. Molecular panspermia is well-attested; outright panspermia is possible; both support (in conjunction with @RobinHanson's Grabby Aliens maths) a once-in-a-million-galaxies stellar nursery in the Milky Way that seeded multiple systems with (the precursors for) life.
   
   Evidence is accumulating in the direction of Mars having once been habitable, and if strong evidence for life on Mars emerged, I would interpret this as strong evidence for the above model. (The probability of lightning striking twice in the same system seems remote. If abiogenesis was that common, we would expect an observable universe visibly—and by visibly I mean galaxies-converted-to-computronium—teeming with life, not our observable universe, in which life seems sufficiently rare that we still aren't sure it's not lifeless aside from us.)
   
   A growing list of Earth-like exoplanets with probable liquid water, the discovery of complex organic chemistry in interstellar space, and the discovery of invertebrate intelligence make many of the old Great Filter/hard step hypotheses untenable, and Fermi's paradox seems evermore baffling, not less. Credible if highly speculative models such as the astrobiological Copernican limit predict multiple intelligent civilisations in our galaxy. Any intelligent civilisation evolving in our galaxy (probabilistically, millions of years before us) would have already colonised the galaxy with sublight von Neumann probes or conceptually similar technology in cosmologically short (perhaps as little as 500,000 years) timescales. My priors for intelligent (perhaps superintelligent and post-biological) alien presence are relatively high.
2. Criticisms of the extraterrestrial hypothesis (such as @Eliezer Yudkowsky's Tweet or Neil deGrasse Tyson's commentary) often have the flavour of HPJEV's dismissal of Lord Voldemort. (For those who haven't read HPMOR, HPJEV cannot reconcile ontology-challenging evidence provided by well-informed individuals warning him about an intelligent immortal dark rationalist with the lack of an extinction-level event, displaying a lack of imagination and general epistemic failure in not considering alternative motivations for Voldemort's behaviour.) They attack the narrow ETH of pop culture (biological aliens hopping in large spaceships and flying to Earth to spook us and abduct cattle), ignoring the fact that ufologists have been arguing against this since the 1960s. Jacques Vallee, J. Allen Hynek and John Keel arrived at similar conclusions to Robin Hanson's attempt at steelmanning the ETH (in which Hanson suggested hidden orbital projectors): UAP events are theatrically crafted apparitions designed to manipulate our beliefs while cloaking themselves with the memetic stealth of intentional absurdity, orchestrated by some kind of intelligent control system that has been present on Earth for the duration of our existence. (I do not follow Vallee and Keel into the increasingly vague "interdimensional hypothesis." Deliberate manipulation of belief via staged miracles is most easily explained by sufficiently advanced extraterrestrial technology.)
   
   If UAP turn out to be ontologically shocking, I doubt anyone will have located the correct hypothesis; possibility space is rather large when it comes to something as complex as intelligence (and conspiratorial intelligence acting in a completely unknown galaxy-level strategic space, at that). Nonetheless, I can think of a few possibilities.
   
   One explanation that would account for the entire observation set—even the more fantastical elements—would be something like an artificial general intelligence (designed for first contact scenarios, civilisation uplifting/handling/manipulating, etc) concealed in an oceanic facility, placed here (and all other life-bearing planets in our galaxy) millions of years ago, constructing and releasing von Neumann probes (or similar) to perform various missions that primarily revolve around shaping the future of our civilisation and manipulating our beliefs using superintelligent awareness of our cognitive biases and how to exploit them. The overarching motivation might be something that we would expect instrumental convergence to produce: power and influence over our species by assuming the apex of our status hierarchy. In this model, the same non-human intelligence that produced the flying shields reported by Roman historians, the flying discs and cigars of 19th century almanacs and astronomical journals, the flying saucers and Butane tanks of the 20th century, and the flying Tic-Tacs of the 21st century would be responsible (at least in part) for ancient, apparition-originating religions and modern UFO religions; aliens would be our gods. Biological occupants would be transient bioborgs, holographic illusions, or otherwise fairly unimportant humanoid interfaces with our species tailored for 20th century understanding. Crashed UFOs would be deliberate hand-offs of technology, or further attempts at confusion and manipulation.
3. Ufology is approximately as niche and extensively developed a field as AI alignment. Those outside the AI alignment niche frequently and frustratingly make confidently incorrect or underinformed statements about alignment. Rationalists make the same mistakes when talking about UAP, indicating few commenters on LessWrong have read even a single book about the subject or engaged with online material to an appreciable extent. Claims that UFOs are an American phenomenon are completely incorrect; UFOs have always been a global phenomenon. Alien psyops are not wild; see Richard Doty and the MJ-12 dissemination, and the Pentacle memo (which convinced Vallee that a secret official UFO investigation was occurring parallel to Blue Book that included suggestions of staging UFO events).
   
   Scientific thinkers in general frequently make uninformed claims about UAP. Stephen Hawking questioned why UFOs only show themselves to crackpots, when even a cursory examination of Project Blue Book would tell you that the most credible cases involve multiple trained observers, e.g. meteorologists observing atmospheric phenomena with theodolites, and are frequently supported by radar and other data. Even ufologists unknowingly parrot falsehoods, such as the idea that extraordinary or "known unknown" UAP comprise only a "small residue" of UAP cases, when Hynek's own assessment of the Blue Book data was very different, arguing that the inexplicable unknowns comprised around 20% of cases, if not higher considering how many cases were classified as resolved when they clearly weren't (e.g. resolving UAP as the planet Venus when Venus was not visible). I will provide a recommended reading list to address common misconceptions when I get around to finishing my planned post on UAP.
4. The evidence for UAP (in the sense outlined in the Disclosure Act) is quantitatively and qualitatively comparable or superior to the evidence for rare atmospheric phenomena such as ball lightning and the Hessdalen lights, including thousands of credible eyewitness accounts (including close encounters featuring multiple eyewitnesses, including astronauts and professors and Presidents, including phenomenologically consistent reports long before UFOs saturated popular culture and planes/drones/balloons cluttered our skies), videos, photos, radar data, sonar data, radiation poisoning and other measured radiological effects, trace physical evidence in landing cases, and molten slag with decently-documented chains of custody. Ball lightning provides a useful base rate against which to compare expectations for evidence for UAP; ball lightning is not trying to be stealthy, yet after centuries of eyewitness accounts, it has produced one blurry video and spectrograph to attest its existence. Skeptics that argue UAP conveniently lurk at the threshold of observability must acknowledge that this same argument can be used against many other rare aerial phenomena that are generally accepted as real.
5. Multiple explanations are probable. A good explanation need not account for every aspect of the alleged phenomenon. Disinformation campaigns and psyops might explain stories of crash retrievals and pilots. Natural atmospheric plasma phenomena might explain most aerial cases. Sleep paralysis and other visionary or psychedelic experiences might explain most alien abduction cases. This does not negate exotic possibilities for other cases, e.g. the 1952 Washington incident or the 2004 Nimitz encounter.

Meta-level high-five for engaging with a stigmatised topic with extensive reasoning, onto object-level disagreement: What better strategies did you have in mind re. achieving goals like positioning themselves at the top of our status hierarchy? NHI would likely be aware of cognitive biases we are not, as well as those we are (e.g. the biases that cause humans to double down when prophecies fail in cults, and generally act weirdly around incredibly slim evidence).

The highest-status authority, in the eyes of the vast majority of humans, is a deity or deities, and these highly influential, species-shaping status hierarchies are largely based on a few flimsy apparitions. (This is somewhat suspicious, if your priors for alien visitation are relatively high; mine are relatively high due to molecular panspermia.) If you had to isolate seeds for future dominant religions, UFO and UFO-adjacent cults (including Scientology and the New Age) seem like plausible candidates; UFOs are frequently cited as the primary example of an emerging myth in the modern world.

If we assume these results are the desired result, we could hypothesise NHI is using its monopoly on miracle generation to craft human-tailored memetically viral belief systems, from ancient gods to today's saucers. Given that ancient gods DO occupy the top of our status hierarchy, beyond our corporate, cultural and political leaders, I'm not sure we can be so confident that creating disreputable UFO reports is a poor strategy; less reputable reports dominated the world in a few centuries.

Thank you for kickstarting an interesting discussion around this topic. I won't bet against you; I, too, think most LessWrongers dramatically underestimate the plausibility of the extraterrestrial hypothesis.

The UK's Project Condign concluded UAP were real and exotic, but were unknown natural atmospheric plasma phenomena (similar to the Hessdalen lights and reports of black or metallic-appearing ball lightning) generating electromagnetic fields that interact with human brains to induce psychedelic/out-of-body experiences (hence alien abduction and close encounter reports). Would this category of explanation (something that accounted for most or all weird aspects of the UFO phenomenon without being especially ontologically shocking in retrospect) count as "very weird," in your view?