Originally, I thought the strip mines were blasting. That is what it originally sounded like. In those cases, and we are about 5 miles from the mines, it is hard to tell if the sound is from the air or ground. However, the mines had ceased operation, and this was the source of my confusion. I also learned my father-in-law, about 2 miles away, could also hear them. Some occurred while on the phone with him, and we heard them at the same time. It wasn't until it was confirmed that the mines were not operational, and the meteorologists said there was nothing in the atmosphere that could explain the noises that I really began tracking when the sounds happened. One night, right before one of the sounds, there was a very loud noise, like a low altitude jet. That only happened that one time though. By the time I got outside, all I could see, and this was the one time there were no clouds, were three very high planes, that appeared commercial in nature based upon size and signal lights. But they could have been any kind of plane really.
It is not unusual for us to have small planes flying around, we have a small airport not far away. Also, we routinely have military helicopters flying around. That would include single rotor and dual rotor helicopters. But like I said, we are not that far from Fort Campbell, home of the 101st airborne unit. I have been fishing on KY lake before and seen planes practicing mid-air refueling. That is something to see in person. I will admit, I was in awe watching them line up, link, and fuel.