Sorry, but that's just ignorance. It's an UAV, it's not registered, has no type certificate. He doesn't even seem to be aware of airspaces.

So no, it's not legal in many ways.

Fair points. I am aware that it is a UAV, and that there are some harsh regulations around the world (e.g. drones are completely banned in Morocco). I am also willing to accept my vast ignorance. I don't know exactly what regulations apply to an autonomous airship: balloon, UAV, recreational amateur aircraft? Actual laws for the handful of countries involved in the actual trajectory (Nicaragua, Thailand, Egypt perhaps) are not easy to find online. So I changed the first paragraph to:

"Finally, what are the legal implications of flying an airship drone over foreign air spaces? This very complex area clearly requires in-depth study and careful consideration, and it lies completely out of my depth. The primary objective is just to avoid being shot down since I'm not planning to visit any foreign countries in person, so allow me to just touch over the main issues."

Ha! It’s also going to be funny when he discovers going over India requires parallel diplomatic clearance by his embassy and if he misses the slot, bye bye record. Repeat problem for multiple countries along the route.