object moved from one point to another so fast that it looked liked there were two of them

it was silver , the shape of a silver dollar. The sun was setting , and i happened to look toward the west, the sky was a dark blue, i saw this disk move up and down , it's reflection is what caught my eye. Then for about 10 seconds it just hovered, i thought it might have been a weather balloon, but when it moved from point a to point b in a millisecond.......i knew then no balloon can move that fast......much less any thing i had ever seen fly .........  then after it stopped at point b , it just hovered for a second or two, then shot straight up in the atmosphere...... gone ...no trail or anything...…
Date may be approximate, although the witness does not indicate that fact.  PD