3 lights in a straight line formation.

Looked up noticed 3 lights in a staight line formation assumed it was a plane as its in the landing path for airport they went out of view due to tree cover. Drove down road a half mile noticed lights appeared again going on then off left to right and as last of 3 lights went out the sky was completely empty nothing there it was a clear blue evening sky so I was expecting to see some sort of object but there was nothing. I live within 4 miles of sighting about 2 hrs later I saw two fighter jets fly over in the night sky while I was outside with my dog.