I'm not sure exactly what the two hypotheses you're suggesting are, but if reports where craft appear to vanish or morph or appear bizarre are true, then the possibilities are:
- The craft really is bizarre and we have no idea about how or why it is that way.
- The craft is a material construct we could relate to on our terms, but is fooling our senses through the use of some sort of active camouflage.
- The craft is a material construct we could relate to on our terms, but is fooling our senses as a byproduct of the way it works ( e.g. some high energy EM field is influencing our sensory perception ).
- The craft is a hallucination caused by some natural process ( e.g. The Persinger Earth generated EM field theory, the ingestion of some sort of hallucinogenic by the witness )
- The craft isn't a craft, but is some sort of rare natural phenomenon ( Earth lights, ball lightning, some rare astronomical event ).
- The craft may or may not be a craft and the strangeness is the result of a natural misperception of the otherwise mundane.
- The craft is an intentionally created misperception ( some sort of hoax ).
Of the seven options above, 1., 2, and 3.. are of primary interest to the core subject matter of ufology ( alien craft ). The rest are of peripheral interest. The question is then: How do we differentiate between what we're interested in and all the rest? The answer is of course, by doing some investigation and analysis of the reports to determine with reasonable certainty which cases are more likely to be alien. Because each possibility has it's own characteristics and properties, it is often possible to separate the signal from the noise, and that is what UFO investigators and analysts do, and they've been doing it since the dawn of the Modern Era.
The chart below spans about five years and takes into account 1,593 of the best cases from 1947-1952. ( source )
So even back in the 1950s there were serious attempts to sort out real craft from other stimuli. However back then there wasn't much emphasis put on the possibility of active camouflage. That is a relatively new concept. Sometimes ufologists, even eminent ones like Vallée jumped to far more fantastical conclusions, like alternate dimensions, instead of recognizing that high-tech camouflage could explain the same perceptual phenomena. It could even explain more bizarre visual sightings like the one @Burnt State mentions here involving what appeared to be a spider-webbed honeycombed looking craft and fish-like aliens.
Because active camouflage is something our own military is presently working on, it's a known factor ( as opposed to more exotic hypothesises ). So when other explanations seem to fail, we still don't have to invoke far-out theories about parallel worlds or the way the mind might be influenced by telepathic waves or whatever. Relatively simple trickery of our senses is certainly possible, and therefore IMO it's the most reasonable explanation for stranger cases. The problem these days is differentiating between which craft are ours and which ones are alien ( if any ), because our own active camouflage tech may be more effective now than what we're aware of.
As we "see" by 2 circumstances. Natural and also hallucination, then we see. As we exist, then we exist in the conditions of change.
If we "hear" by 2 circumstances. Natural and artificial, then we hear.
When we exist as a healthy body, healthy mind....and also as a changed body and a changed mind, then we should ask why?
If we hear naturally and then hear abnormally and the 2 circumstances demonstrate....1. by fact of inheritance, or 2. by fact of artificial interaction then the physical result determines the reality....it actually is happening. If a human hears abnormally due to being physically/chemically altered (called a mental condition), and a healthy human being also hears abnormally, then the only condition that allows the difference is the "artificial condition".
What condition exists as an in between condition on Earth that is not natural and called artificial? Science does, in acts of its own conversion of matter from a higher to lower condition cause an effect of "in between states or transmitted nuclear sounds".
Therefore is it any wonder that the natural living organism is affected by an introduced and artificial condition that changes the natural states that life belongs to on Earth...evolution and natural cooling/fusion statuses?
The ancient occult awareness, from being attacked stated that the hearing of voices was an introduced and abnormal condition to the natural life. It also stated by observations that the rational of the male mind was altered due to the introduced condition. If the chemical brain is changed then thinking changes and so does the hearing of sound.....atmospheric feed back demonstrates by photon recording of voice/image that a human hearing voices is not due to some symptom, it is due to being artificially altered that allows the atmospheric feed back to be heard as a condition.
As the black triangle converting atmospheric body demonstrates...the ancients determined the building of the pyramid by PHI as part of the applied science, along with the temple layout plant to belong to ancient occult practices, with the pyramid having a sun or orb above its point (triangulation)...with an eye...and the eye "sees". The gases when changed in the atmosphere converting as a wavelength to attack the natural gas and ground fusion would demonstrate gases burning, forming different colored lights in the triangulated signal. The darkness of the same triangle at night demonstrates space is caused by the removal of the atmospheric gases in an interaction.
Wisdom...the human mind/brain gaining recorded imagery and advice for invention as a plan/design from the atmospheric image recording and interactive feed back. Suddenly the occult mind gains information for the building of a dark triangulated plane that can cloak itself. Which would demonstrate that the same outcome would occur for the forming of the triangulated signal, where the information came from. The metal interaction would therefore remain hidden in the atmospheric body, until it is caused to be seen.
If you review the different circumstances for the triangulated signal to be seen as a metal object....1 is by plane movement altering the natural atmospheric body, where suddenly a UFO emerges....or when the atmospheric body allows the emergence, which probably would relate to the burning of nuclear fuel, the changing metallic bonds in natural Planet Earth fusion.
If an atmospheric body can produce a manifestation of a metallic object, then you would question the reality of the observation. Yet the observation and the fall out has always been quickly dealt with in secrecy and then the public ridiculed who observed the manifestation and fall out of the object.
As stone is fused with crystalline structures and metal, and out of space also has different forms of stone, then out of space must also have different forms of metal in comparison to Earth's natural fusion.
As particles fall to Earth as dust from out of space, then the dust demonstrates it is neutralized. This observation would be due to the condition of dust on Earth, being nuclear.
What would neutralized larger metallic nuclear particles forms, if not dust....due to the mass of the atmosphere and also how cold it was....causing cooling and then disintegration of the metal/nuclear. As the Earth's atmosphere demonstrates it has heated, then the manifestation would be a real physical observation.
If we are removing the natural fusion of stone...which metal is a part of and then witness metallic O bodies forming ^ in the atmosphere, then it is obvious that the atmosphere is no longer protecting Earth from out of space fall out.
As we all can review the new occult sciences, they want to believe that metal can disappear out of Earth's fusion and then reappear as a held fused stone state after their collider has gained energy. Metal never existed when energy was first formed, nor did stone. Their collider experiments want energy when no metal and no stone existed, do some research on their theories. Is it any wonder than unnatural effects are occurring from their experiments?
Therefore the anomalous effects of occult practices, known as phenomena are real, because the only unnatural circumstance to life being lived on Planet Earth is the choice to convert the natural fusion of Earth's evolution.