While carpooling with Mom and Dad through East Helena, Dad saw it first coming in from the south. He points it out, and we think it's a plane. I found the light configuration was odd, being four bright white lights splitting the object into thirds. The span between the two lights at the ends was about the wingspan of a 747. I noticed that the lights were in a slight arc formation, as if they were on an invisible wing. There wasn't any blinking, no red or green, or any regulatory Anti-Collision lights, just the four whites. The object arced westward, by then I figured it was making a landing at the airport. Instead it increases speed, crossing the entire valley within a second. There were no booms, or flashing indicating a sonic boom. I would say the way it zipped off was sort of like it was magnetic. Everyone in our vehicle couldn't stop talking. Dad remains skeptical, Mom is indifferent, I am left shaken with excitement with the encounter. We were too excited to take pictures on our phones.