The thing was a long string of lights moving in a line (Google ufo long string of lights)

So I'm in my back yard. There is a sweet 16 going on in my neighbors backyard. I don't take notice of their excitement at first because they're talking about a centipede or Santa. Then my sister in law and her friend who are out there too start saying woah what is that?! And with my interest stirred I looked up and saw what was a long sting of lights in the sky moving across the sky at the same speed and length apart (which indicates to me that it is a large aircraft of some type- too large for us humans). By the time I got my phone out it started to disappear one light at a time from right to left. My sister in law did get a picture of it luckily.