UFOs try to hide, but they're not very good at it. If they are the products of a highly advanced technological civilization, their efforts to hide should be foolproof. But they do get seen, detected on radar, and even photographed. So--- what gives?
One set of possibilities that rarely gets considered is that UFOs may be leftovers from extinct civilizations. They may even be experiments gone awry from surviving exo-civilizations. Or they may be automated machines that have somehow gone rogue, either through defects, damage, or unforeseen consequences of their built-in artificial intelligence features.
If anything like this is the case, then it becomes easier to explain why UFOs seem to behave irrationally. Simply put, the UFOs that we do see are indeed irrational. They are programmed to avoid detection, to avoid capture, to avoid crashing, but otherwise, they sometimes act in ways that cannot be explained in logical terms.
Another possible explanation for some "alien encounters" is that the
supposed space aliens are experimental half-human half-animal
hybrids from secret laboratories on earth. This is perhaps the
last and final frontier of "forbidden science."
Going back at least as far as the 1920s, suggestions were made that such
half-human creatures could combine the basic intelligence of humans with
the strength and obedience characteristics of certain animals, most notably apes.
In the 1930s, succesful experiments proved that under certain conditions,
human egg/sperm could be combined with animal egg/sperm in a test tube,
and made to grow to a certain extent.
When news of this leaked out, there was a public outcry, including from the
Pope. The experiments were supposedly halted, but in all likelihood, continued in secret.
One hypothesis is that some form of anti-gravity or artificial-inertia has been
developed that can endow aircraft with extraordinary flight and maneuver
capabilities--- but that the force field produced by such propulsion is fatal after
only a few hours of exposure to it.
Enter the expendable half-human, which has no legal protections.
Such creatures could be intelligent enough to be trained to fly and maneuver
over simple courses. But between their own limitations, and the limitations of
experimental aircraft, the occasional mishap is to be expected, accounting
for some of the sightings and crashes.
With the recent developments of drones and computerized artificial
intelligence, the need for these "biological" pilots will rapidly decrease,
except in the case of bio-computers which use brain tissue to form processors.
All of this is, of course, pure speculation.
Please excuse me now, there is a knock at my door.
My oh my, why are both those men at the door dressed in black suits?
Hey! Where are you taking me? Let go! AAAAAHHHH!!!!
from an undisclosed location