Jennifer Grosman shared this article, Welcome to the Drone Economy. You might say the sky is the limit, but drone usage and robotics are going way beyond UAV aircraft. There are drones on wheels and drones in the water.
I did not realize there were already drones on rails, until I read this quote about their use in British Columbia, "Remote-controlled locomotives have long been used in switching yards." Sorry Dad, I guess you would be out of a job, but then if you were still alive, you'd be 96!