While this sounds like a cool idea, my first thought is: What happens when someone is able to remotely gain control?. Does the plane not accept commands other than "Please fly to point X. If you can't contact me again, land at Y." or can you send more complex instructions like "Fly at this altitude and heading"? If it's the latter, that is basically "joystick level" control but with more steps.

There will always be vulnerabilities in hardware and software and when they used the term "encrypted satellite", I worry that there is vulnerability in there somewhere. Even something as simple as a phishing attack of pilots could lead to dangerous outcomes.

Nevertheless, I'm sure there will be a Defcon village for it in the next few years.