Huge blimp-like craft; lights around the middle of craft; no sound; hovering above the highway.

I filed this away for a long time.  In fact, I'm not sure of the exact date except that it was either in 1969 or 1970, late in the evening (it was also reported in The Washington Post the next day as an experimental aircraft).  What prompted me to report this is the recent Sarasota, FL incident, where a man reported seeing a huge blimp-like craft near Myakka.  He described it hovering above him.  I began to think about what I had seen and decided to say something.... I was driving west on Rt. 50 toward Fairfax.  My friend and I both spotted this thing "hovering" over Rt. 50, with lights that seem to revolve around the center of it.  We slowed down to look at it.  It looked like a blimp, but wasn't.  It made no noise.  Unfortunately, we didn't stick around to observe it better.  But, I am sure this was no experimental craft.  I have never forgotten this incident and I have never seen anything like it since.  I spend a lot of time in Sarasota and from now on, I am going to spend a lot of time outdoors in the wee hours of the morning.  If you should know anything about this incident, I would love to hear about it.  Thank you for listening. ((e-mail address deleted))
Date in either 1969 or 1970 is unknown.  PD