Hovering over the Nuclear Plant

Lake Dardanelle State Park Supt. and I were patrolling the park (across Lake Dardanelle) from the Nuclear Plant when we noticed three sets of red lights hovering over the cooling tower of the nuke plant.  
We remarked on how dumb those, what we thought were helicopter pilots, guys were to be hovering over the nuke plant.  
Then we realized they weren't aircraft.  We watched them for about 10-20 minutes, when they suddenly flew across the lake, about 3 miles distance, in about 1 second.  
They hovered over a mountain for about 5 minutes, when they suddenly flew back across the lake immediately over the nuke plant cooling tower again and came to a dead stop.  
They hovered for another 10-20 minutes, then went straight up out of sight. 
In those days, people thought you crazy for reporting UFOs, so this is the first report of what we saw that night.
Witness indicates that the date of the incident is approximate.  PD