First encounter happened some time in the early 1980's.

My boyfriend (at that time)and i were leaving Las Vegas and had entered the desert. He was driving an old van. I was slumping down in the seat and had my legs bent up on the dashboard so I could see the sky. There were no lights out there that I remember. It was very dark with no traffic and the only lights were from his van. 
I was looking up at the sky while he was driving, as it was very late (sometime after midnight at least)  All of a sudden a small perfectly round disk shaped object swooped within a a foot or two right over the front of the van from nowhere. It made no noise and had no lights. The lights from the van reflected off of it. 
I can only describe it as about 10 to 15 feet perfectly round and it had a bottom that looked like a raised waffle iron and made out of the same type of tephlon type material. 
I only saw the underneath. I had my boyfriend pull over but it was gone and he never saw what I saw.
Witness indicates that date of the incident is approximate.  One of three reports from same witness.  PD