A few years ago (back in 2014 I believe), I read about a new drone that could follow you while you wear a transponder. It was called AirDog. It seems to be vaporware (not real yet).
This drone would make creating videos of you skiing or jet-skiing or any number of other outdoor activities amazing. I really wanted one, but apparently to date they still have not shipped any drones! I heard about “beta testers” getting drones in 2015, but I haven’t found anyone that has actually received anything. It seems to be vaporware, too bad! I can’t believe it is over 3 years later and they still haven’t made a product!