Why? Just because nobody will be able to find the difference
between Unidentified Flying Objects and robots : drones, insect-like robots,
nano-robots, you name it.
Nothing is what seems to be. The UFO=alien spacecraft legend
is a good invention for the 50’s.
“This "robo-fly", built from carbon fiber, weighs
a fraction of a gram and has super-fast electronic "muscles" to power
its wings.
Its Harvard University developers say tiny robots like
theirs may eventually be used in rescue operations.
It could, for example, navigate through tiny spaces in
collapsed buildings.”
Just keep those Exopoliticians and fantasists in the attic,
where you have the old radio and the pulp-fiction magazines.