For the aerial craft hypothesis to be true we would need to address multiple factors that we simply don't have any answers for. This isn't stealth bomber territory where you can say after the fact "It's a plane made out of new stuff, in an unconventional shape", this is stacking multiple problems one on top of another.
At the very minimum we are looking at novel propulsion technology that defies our fundamental understanding of physics. Masses that move at ludicrous velocities and perform hard stops, turns, and accelerations. That energy has to come from somewhere, and it has to go somewhere. Consider how other objects that move fast (especially ones that go from stationary to supersonic) behave. Why aren't our UFOs acting the same way? Where's the sound, heat, shockwaves, etc. from all this movement?
Even if there was some lower mass involved we'd still have the problem of power generation. Where's the generator? That thing would be huge, and it would have all the same physics problems the propulsion did.
We have to start with the most fundamental questions first. If this is breaking physics (and it appears that could be so) then how might it be doing so? Are there any more plausible explanations? If it isn't breaking physics, or if even a smidgeon of conventional physics applies, then where should we be looking for evidence of that (for example: if these are projections, where's the projector)?
Masses that move at ludicrous velocities and perform hard stops, turns, and accelerations.
What I'm thinking here – in the form of the proposed hypothesis in the question – is that the anomalous movements are anomalous relative to aircraft, which, until recently, were all piloted (as far as the 'public' knew). Un-piloted craft are capable of (relatively) "hard stops, turns, and accelerations" that pilots can't physically withstand.
If the movements people are observing really do consist of "ludicrous velocities and perform hard stops, turns, and accelerat...
Do UFOs need a single explanation? Just because we have one label on our map doesn't mean the underlying territory is unified.
Nothing needs a single explanation, so no. But this seems pretty uncharitable as-is; or maybe a kind of covert radical skepticism. Or maybe I'm just failing to think of a better set of multiple explanations – what is yours?
To clarify, by "UFOs" I was thinking of what, in this answer, is referred to as "Masses that move at ludicrous velocities and perform hard stops, turns, and accelerations.".
Obviously, there's a big space of possible objects that could be considered 'UFOs':
My question is implicitly ignoring [2]. It's also ignoring 'mundane' instances of [1], e.g. weather balloons, (early) experimental aircraft, stealth/spy aircraft. Those seem all accounted for by reasonable common-sense explanations, e.g. someone saw an aircraft they didn't recognize or couldn't clearly identify.
The specific subset of [1] that didn't (at the time) seem explainable as aircraft, because they (seemed to) move in ways that aircraft can't/couldn't, seems much more likely to me to be people observing drones, e.g. un-piloted aircraft. And, given that UFOs (by definition) can't be clearly identified, it seems likely that observations about them might be inaccurate, e.g. because their distance, velocity, or movements might not be accurately observable (especially given the salient comparisons available to observers). So what seems like objects that exhibit "ludicrous velocities and perform hard stops, turns, and accelerations" might well just be un-piloted aircraft that can exhibit a smaller degree of those same characteristics (because they're not constrained by needing to not kill or injure pilots or passengers).
Obviously this couldn't explain things like, e.g. Bob Lazars claims.
Hm, so roughly speaking, how would you break down the probabilities of some different explanations, given a generic UFO sighting? E.g. just a shadow or reflection, natural object in the sky, man-made stationary object, human-piloted airplane, drone, actually aliens? Is there some common sub-type of UFO sighting that you think has low probability of all non-drone explanations, even accounting for all the faults of human memory and character?
I don't know enough about 'generic UFO sightings' to answer.
"actually aliens" seems very very unlikely – definitely not literally impossible tho.
My priors are that a lot of historical UFO sightings really were experimental aircraft. I'd expect some number were early drones too. Others seem to have definitely been, e.g. weather balloons.
Other sightings, particularly the relatively well-documented recent ones, seem very similar to 'ball lightning', which is also so little understood that it's not even clear that it's real. Assuming those observations are both accurate (e.g. the relevant 'equipment' was working correctly) and being interpreted accurately, they don't seem to be drones, unless the drones themselves include novel propulsion systems (which is very plausible assuming the existence of such novel systems).
(And, as a a kind of reference point, 'rogue waves' seem to have been similarly so hard to study, until very recently, that their existence wasn't entirely clear.)
Another post by Tyler Cowen on UFOs:
Cowen's post is (partially) replying to a post by Robin Hanson:
From Conversations with Tyler 2020 Retrospective (Ep. 112) | by Mercatus Center | Conversations with Tyler | Dec, 2020 | Medium [emphasis mine]:
I'm sure I've run across that idea before – that UFOs are drones – but encountering it just now (again?), and thinking about it (again?) ...
I'm relatively convinced – UFOs are 'just' 'drones'.
They're 'just' drones – it wasn't 'obvious' before and, if a significant number of historical UFOs were drones, the drones are impressive tech!
Possibly the drones were much more than even contemporary drones known to the public – so not just (regular) drones.
(And it's still of course possible that some of the drones were extraterrestrial – and maybe much more likely than UFOs being sentient-human-plus-intelligence-in-the-flesh piloted or occupied.)