Star-like lights moved together over Air Force base in a V formation, then suddenly began to separate and then just go dark.

I was looking up at the stars last night when I noticed a satellite above. I then grabbed my cousin and uncle who were there with me to see it.  As I was trying to spot the slow moving dot in the sky I noticed a group of stars which I thought was just a constellation start to move south across the sky.  This group of stars was in the shape of a V and spaced almost perfectly apart.  As I frantically tried to point the group out to my family the stars began to separate and then suddenly went dark.  At that second my uncle found the satellite and the group was nowhere to be found.  My uncle lives right by DIA and the Air force base so I know what planes, helicopters, and even jets are capable of. None of those could have gotten as high as these lights were, and if they were anything humans make why did they just go dark all of a sudden instead of staying lit up like the satellite.