Asatched the light travel back and forth and uyou could see no craft. When the light went off, oh my God.

I was off duty in November, 1979, deer season, working as an undercover vice officer.  I was traveling from a friends house and we spotted a small light on top of the hill above her house moving back and forth across the ridge.  We watched the light for almost two hours.  It went or traveled back and forth and up and down in a very slow fashion.
An airplane started toward the craft and the unidentified object shut down the light and to our amazement the craft became very visible and moved very swiftly over our heads away from the oncoming airplane.  The craft was huge, you could observe the indentures of the giant steel structure pausing over our heads.  I would estimate that the craft was larger then thrre football fields combined or larger.
The plane came closer and the craft took off in a southern direction faster than the speed of light. Their was no engine noise. You could see the craft fly out of sight for miles as a big black machine in the sky.
I called the airport and advised them I f they had any reports of a UFO and they denied any planes being in the area.