Comet-shaped floating object flies toward Washington, DC.Fireball might not be the best description - more like a bright white comet-shaped object (short tail) that seemed to float in the air as it moved at a good clip. No sound and no contrail. I observed it out of my right view as I looked south (on my way to picking up Chinese food). I had seen similar objects the day before (November 12 - Bethesda, MD report) and on November 5 (Bethesda, MD report) and October 15 (Kensington, MD - report not filed). The white object was high in the sky - no clouds were present. It was moving from right to left (West to East). Wheaton, Maryland, is about 4 miles directly north of Washington, DC, and the airspace is pretty restricted. The object veered - or more like pivoted - southward, as if heading toward DC/Virginia. It then completely dissipated. It looked like it vaporized. Not fading slowly from view, but gone. I took a video of the incident. The other times I saw these objects, there were either three or four together, maybe a few miles apart from each other or closer. They may be in one field of view - kind of close but distant from each other. It's weird - you see just one, and then there will be three or four in view. These appear to be the same things described in the Philadelphia, PA November 5, 2016 17:15 report of four cigar-shaped objects. My report of November 5 was from an hour later (DC is south of Philly and the things were traveling southwesterly when I saw them).Here are their characteristics from my four sightings: no sound; very high; very large; "soft" (not hard outlines); bright white - likely reflecting the sun; no contrail or vapor trail; appear in groups (three or four) sometimes (first one and then the others); not in same "space" as other aircraft in the area; looks like a slant sometimes; flies slanted; changes directions with pivots and not regular turns; seem to float, but also move fast - alternately and at the same time; no discernible body; tail is short at times and longer at other times, likely due to perspective as it rotates or moves from you; tail can appear to be a sideways V when viewed from one angle and straight - like a slant - when viewed from another; does not have lights (as if the objects would not be seen at night); they are being flown, not drifting - movement is purposeful; at least one seemed to disappear (vaporize like a puff either through rapid acceleration or otherwise); my vi! ewings were in late afternoon, early twilight (coincidence?).I'm ((deleted--fifties)) and never have seen a UFO until these four incidents.