am also a retired Air Force officer with experience observing day/night aircraft operations, ICBM launches & re-entries. This observation did not appear to be an aircraft landing light although it did resemble a reentry vehicle. It was as bright as an aircraft landing light, which I'm accustomed to seeing frequently over the Potomac River, since I live south of Washington DC and often see airliners on final approach to DCA airport. However, those usually appear bright just for a second as the aircraft turns head on to me then fade quickly as they then turn northbound, when I'll usually see their anti-collision/navigation lights. This fireball was as bright as a landing light as seen from a mile or two, but was distinctly elliptical in shape and moving from north to south in my field of view, with a small trail behind it (perhaps a few degrees in length). What was especially interesting was the heavy degree of cloud cover this morning (unable to see any early morning planets like Venus or Jupiter that I usually see in the southeast when I'm leaving around 06:20-06:30L to catch the train)...this fireball was either in a small area between cloud bands or may've actually appeared to be below a higher altitude cloud layer at a lesser distance(?)...difficult to gauge the parallax as to the clouds' altitude and distance in the dark, but the cloud layer was about 30 degrees above the trees, and the fireball was seen just above the trees.