disk shape ufo up close I saw every detail of the ship

I was sitting in my granpa's passinger set and he taped me on the sholder.  He pointed to my right and I looked over.  About a 150 feet over to my right thier was a disk shape ufo flying about 50 feet off the ground at about 45 miles per hour.  It had larg squar sheets of aluminum mettle.  It was so close I could see it hade rivets in the squar sheets of metale.  It had gold tinted windows that rotated and when they rotated around I saw the non humanbeings and I could tell they where looking at me.  As my grandpa drove forward we started to go over a bridge with rail road tracks beneith it, as the bridge whent up the ufo stayed it's course.  I leaned up in my seat to look at it longer but as the bridge got higher my view of the ufo disapeared.  When we came over the other side of the bridge I never saw it again.  I think the clear view of the rail road tracks was used like a magnetic run way for the ufo?
Witness indicates that date is approximate.  PD