This is cool. A time lapse, aptly named Highway in the Sky by the guy who filmed it, shows how different layers of clouds in the same sky can actually move in completely different directions. It's like seeing clouds respect different flows of traffic. It's like seeing multiple skies in one. It's like staring at a computer program in the sky.
The phenomenon is known as differential advection, which is basically when two or more air masses have different wind directions. Whatever it is, it's really cool to watch.