I have been doing some chair research and i am convincedĀ
they are what its called \ Active Camouflage technology.
Its next level stuff, not only it hides the plane but it also displays an image in a different place that can take different shapes/sizes
and be detected by radars as a physical object.
There are some studies out there about the possibility and i wouldn't be surprised those UFO's are exactly that and its the next step in cloak technology.