Witnessed 15 disks flying directly west into the setting sunlight

My friend and I had our families at Bull Run Battlefield Park for a kite festival.  The kids flew their kites and many adults also flew kites and we had a nice picnic.  They were giving prizes for the best kite, the highest flying one, etc.  They even had a hot air baloon for the kids.  Anyway, about 5 pm, the announcer told the crowd that one of the kites was caught in a "thermal", a hot air convection and was about 800 ft and going up.  So, everyone is looking up and I was eating.  I stopped, looked up and saw some white bugs in front of my eyes, or so I thought!  I refocused and suddenly realized that I was focusing on some silver dots flying about 30,000 ft up.  They were going from east to west directly into the soon to be setting sunlight. I think the sun set at about 6 or so.  Anyway, 2 of the disks suddenly moved quite a bit ahead of the others, which seemed to be swarming.  They then were lost in the sun.  My friend came from the other side of the park, about a mile away and asked, "did you see those things flying up there?"  He said all the people were really excited about seeing something, but it happened so fast that you didn't realize what you were seeing until you actually thought about it a bit.  They looked EXACTLY like the old movie of the UFOS in Montana in the late forties.  Silver dots and I would say they covered half the sky in 10 seconds.