Triangle craft flying over Haltom City, Tx. 11/01/1979

Triangle Sighting Haltom City, Texas Date 11/01/1979 (close approximation of date)  I was 11 years old in 1979 playing in the front yard at night with my brothers at a friends house in Haltom City, Tx. After we tired ourselves out they went into the house, I stayed outside to sit on a front lawn chair facing east.
While there I glanced up and saw this triangle craft moving silently with what looked like port holes on each corner and some kind of circle dome in the center. It moved like a boat swaying back and forth on water. Heading west very slowly with no lights on. I watched it for about a minute or more it seems because I thought there was something wrong with it, like it might crash.  The city lights lit up the under side of it because I saw it in very good detail. ( may have been 2000 to 3000 feet up). I got excited and ran into the house to tell everyone that there is a UFO flying over and must come out to see. But they all laughed saying there is no such thing. I went back out to look for it but didnt see it, and then a few seconds later a Helicopter appears and is flying around lower than the triangle, shining its spot light on the ground. I thought to myself, this is all too weird and was time for me to go back into the house.
Date is approximate.  PD