I saw something very similar a few years back...a HUGE array of lights moving very slowly and low to the ground.
I have no idea what the heck it was, but being in the country I'm pretty sure it wasn't some king of blimp.
We're a little over 100 miles from Fairchild AF base, which has caused me to wonder if that is a connection to the weird things I see in the sky around here.
That's pretty freaking cool. Maybe multiple synchronized drones, or as you say, a blimp? But the lights, though close, do not have a uniform appearance.
I'm curious.
Beware the man who has one gun, he probably knows how to use it.