String of objects silently moving through the night sky

Took the dog out to pee. Looked up to the west at the stars and saw a stream of lights single file traveling at a slow rate of speed moving from south headed north. There was no sound.  They would appear from the south travel north and disappear.  I ran inside to get my phone and came back out to take a video but couldn’t see any on my screen.  So I ran back inside and got my camera and though I couldn’t see them on my screen I was able to get one picture of one of them.  After they had all flown by I called my wife to tell her what I saw.  I came inside for a few minutes and went back outside for another look.  I saw them all at once at a high altitude in a single file making like a single line.  Then they faded out.