Black Triangle Sighting in Murfreesboro, Tennessee on March 8th 2015 – Two aerial crafts delineated against night sky by lights of triangular pattern move above us

Friend, who is a former Army Special Forces and now attorney, and myself, a retired RN and now music business executive, were driving to his home in a rural area of the largest rural county in Tennessee. He noticed the lights in SE sky and commented on them as being unusual~ something he hadn't seen before. I too, hadn't seen anything like them. As we drove down the dark country road to his small farm, the object seem to be slowly moving across the sky and rather than park the car when arriving home, we drove to the back field of the property which is flat and unobstructed by trees and other topography. We get out and sit on the hood of his car and watch over the course of an hour as the craft accompanied by an identical one track across the clear spring sky. We decided the second craft was behind the first upon initial siting. He asked me if I could hear anything. I listened and noted outloud that the crafts, based on size and relatively low altitude should be projecting engine sounds. He agreed and this is the first thing that seemed objectively odd. Secondly, the speed of movement, again , based on altitude and size of the crafts seemed to defy what he and I know of physics. The track across our line of sight of approx. 25 miles seemed too slow..which suggests they were beating the laws of gravity. The arrangement of the triangular lights and what appeared to be a shadow of a structure of craft of more square or rectangular shape , dark in color was another oddity to us as we both know something of the necessity of spherical shape to make an object's aerodynamics compatible with flying. I was a part time high school advanced math substitute teacher and know enough to know, I can't explain the aerodynamics of these craft and neither can my friend who jumped from planes during first Gulf War. Before they reached the horizon to the NE (towards Nashville, TN), they vanished. No descent to land. No MachIV verticle ascent to the stars. Simply vanished. Higher in the night sky, during this event we noted the path of 2 commercial aircraft at altitudes well over 25-30k ft, and even they ,upon passing directly overhead, could be heard on that night. There is an AF Base in the general direction from whence they came, but operations are rare and involve large cargo carriers. The Nashville BNA airport is NE but the crafts vanished well before a probable descent there. In fact , since weve observed that no commercial craft can be seen making its descent, day or night from this location as we are simply too far away and we've noted that there is an altitude difference roughly half way between this location and Nashville BNA airport where we are just above sea level and the airport is slightly more than us. We were not scared or did we fear for our safety. The craft did nothing to suggest we were of note to them. We are neither skeptics or believers of UFO's though since we've discussed the possibility the military may have developed crafts that can only be tested at night. But, the lack of noise? Ive asked around...this is an oddity noone can explain. The ability to be have such mass and yet move that slowly at an altitude no higher than a helicopter? Odd.