UFO in contact with commerical airliner

I was about 10 years old at the time this happened. I am now 20, but I remember the event like it was yesterday. A few friends and I were outside in the cul-de-sac we lived in when I looked up to the NE and saw a commerical airliner flying above the hill NE of town. The plane appeared to just be a normal airliner (Boeing 747, etc.) I also noticed something behind the plane, it almost looked like the plane was towing something. There was a thin black line from the rear of the plane to a dark saucer type craft behind it. The object was only about 100-200 feet behind the plane. The plane and the craft continued for about 10 seconds, then the black line disappered, and the craft suddenly accelerated going underneath the plane, shooting right up in front of it, then drifted down over the other side of the hill out of view. Ever since that day, I have always believed in UFO's and life outside our own!!!!!
Date of event is approximate.  PD