Recent "Unidentified" S2E06 had an interesting segment.
They (AATIP staff) brought in a retired CIA engineer who talked about a system that could "spoof radar tracks". Make one plane look like 10 or 20, or 50.
It was called NEMESIS (Netted Emulation of Multi-Element Signature against Integrated Sensors.
Seems after an active RADAR system transmits a radio burst, it then pauses and waits for an echo. NEMESIS would send a reply directly to the RADAR sensor emulating various solid objects.
It sounded a LOT like the Navy pilot and/or Navy RADAR operators who were shouting "Oh my gosh, there's a whole fleet of them...".
Didn't explain "eyes down" sightings, but for the people only reading RADAR scope data... could be something.