Helicopter shaped object with twirling red & yellow lights over head, 150' above ground and running silent.

There were two of us in my car driving home ward at dusk.  We had just turned onto a road heading west when we saw a helicopter type object just above tree tops heading west south west.  It was no more than 100 yards ahead of us and 150 feet off the ground, so we got a very close look at.
The main structure appeared to be a muted gray against evening sky.  What was very striking was twirling red & yellow lights up above, like what you would see if bulbs were fixed out at end of a main helicopter rotor; lights steady with no pulsations.  There were also red running lights along the left hand side.  Since this object crossed our path at an angle, so we never saw the right hand side.  What ever this was, we could not hear any noises greater than that of my car although the object flew by so close to us.
Decades later, I found two other people that probably observed the same object just minutes after we did, based on their description, location of their sighting (1.5 miles away from us) and the year of event.
Witness indicates that date is approximate.  PD