"Helicopter" Lights are completely silent while moving very slowly through night sky.

I noticed a large bright reddish star outside my dining room window. I brought it to the attention of my  parents, a retired middle school teacher of 32 years and a retired Corrections Officer/truck driver turned truck driving instructor and certified license examiner.
We watched the "star" flicker between reddish orange and white as it slowly moved East across the sky.  My father noted that any plane moving that slowly would have fallen from the sky.  The light dimmed as the "star" turned South and began moving faster toward our house.  My mother and I quickly went outside to see if we could see the actual craft instead of just the light.  It changed course slightly, instead taking it higher and further to the side behind some trees rather than directly overhead.
We never heard the sound of a plane engine or rotor of a helicopter.
As we were watching the "star" through the trees now heading Southeast, another object flew Northeast overhead very low but much quicker.  It looked like the lights of a helicopter, but again, absolutely no sound.
We are very accustomed to hospital helicopters flying overhead between Rocky Mount, Raleigh, Durham, Chapel Hill, and Greenville at all hours. We know how they look and what they sound like. We know the sounds of the occasional military helicopter making a night flight.  These lights looked like helicopters, but moved too slowly and were completely silent.
This is not the first time we have seen lights with no sound.