Bigger than fullmoon sized yellowish-silver sphere flying over house at dusk seen by boy on bycycle.

I was a boy of 7 years old, riding my bike on the street in front of my home.  I remember it like it was yesterday.  It was at dusk, still very much daylight I was busily pedaling my bike from a dead stop ,and looking toward my right.  Suddenly popping up over the eastern horizon directly in my sightline came a moon-like object yellowish-silver in color and moving very fast, it flew right over my house and disappeared behind the tree line on the western horizon.  It probably took 12-15 seconds from eastern to western horizon.
 In comparison it was bigger than any full moon I've ever seen.  It also had some sort of protrusion at about 2 o'clock resembling an elongated "Z" like tail approx 1/10th the diameter of the body of the object.  I had not even heard of flying saucers at this point and told myself that it was a comet because a comet was the only thing like this I'd ever of which had a tail.
 I saw what I believed to be a similar object 30 years later.
Witness indicates that the date is approximate.  PD