I was thinking in terms of taking a photo.
But then again, a number of things that are supposed to be moving on layouts rarely do: people, cars and trucks, birds, windmills, flags, trees bending in the breeze. Sure there are ways to animate all these things, but I find that repetitive motion more distracting than those objects remaining static. I can choose to focus on the motionless cars and trucks on the highway next to the tracks and choose to imagine them speeding by or idling in rush hour traffic.
We already use our imaginations and the suspension of disbelief to descend down into the scene on our layouts, so I don't see it as much of a jump to imagine air traffic or vehicle traffic in motion.
Just my opinion...