Strangely, there does not appear to be any established internationally agreed upon upper limit on sovereign airspace. We claim ~60k ft but China claims all of the South China Sea. Claiming something doesn’t make it reasonable. We extend our territorial waters 12 mi off shore horizontally. Based on that, a reasonable sovereign airspace limit might be 12 mi above the surface vertically. That’s right about where this thing is drifting I believe.
It’s certainly a gray enough area that we should refrain from blowing stuff up unless it is posing an immediate threat. By our own standards we shouldn’t care if we are survielled. I think we should have treaties defining an agreed upon airspace limit before we start shooting stuff down. What if China wants to claim that space shuttle and ISS overflights of it’s country are threat? What if they claim their airspace extends 200k miles?
I don't disagree with the points that you have made, but in regard to Sovereign airspace - There is no gray area. The Chicago Convention established the International Civil Aviation Organization (ICAO) back in the mid 1940's. Which China is a part of. That agreement established Sovereign airspace over each country. Whether it is recognized or not is another story.
As far as U.S. Military aircraft capabilities, the F15, and the F22 have service ceilings in the mid 60s.
The fact that the balloon has been over the U.S. for more than a few days tells you the capability/ ability of China to manipulate the winds to navigate the balloon.
Google did a lot of experimentation with this over the last 10 years. They put balloons up into the air and learned to move them up and down to keep the balloons within a specific geographical region for days and possibly weeks. The idea was to provide internet/ cell service to remote areas. If I remember correctly they did deploy this technology over Puerto Rico after one of the hurricanes.
