No, it is not. Here is a little factoid not many talks about...
Vertical territorial airspace is as much as a country can exert PHYSICAL
control. Horizontally, territorial airspace ends at the country's borders, but upward? The higher you can exert PHYSICAL
control, the more you can claim how much is yours. The general acceptance is about 60,000 ft limit. Higher than that, it is somewhat open to interpretation whether a country can claim jurisdictional authority. The keyword is 'jurisdictional', as in law.
Being able to go to X altitude does not qualify as physical control. You have to be able to go a certain altitude, loiter around to make your presence known, challenge or put down challenger(s), and you must be able to do that under any condition, not just clear sky. Missiles do not qualify because they simply destroys. To exert control means you have the ability to let some lives and some dies at your pleasure. What restrains you are YOUR
laws, not anyone else's.
60,000 ft altitude is actually quite difficult to control despite how much monitoring you can do. Air density at 60,000 ft is quite low and less air means more fuel to burn. So if you do not have a jet engine that can sustain itself so you can loiter around, you essentially do not have control at 60,000 ft and higher, which mean anyone can fly over your country with relative impunity.
At the time of the Chinese balloon shoot down, the F-22 launched a Sidewinder at 58,000 ft...
A U.S. Air Force fighter safely shot down a Chinese high-altitude surveillance balloon, Secretary of Defense Lloyd J. Austin III said in a written statement.
The F-22 fired the Sidewinder at the balloon from an altitude of 58,000 feet. The balloon at the time was between 60,000 and 65,000 feet.
As of now, the world understands that the US can decide who lives and dies at 60,000 ft and probably up to 70,000 ft over its land territory. This is actually bad news for the rest of the world because if you cannot control your country's airspace up to 60,000 ft, we can overfly you at our convenience. I do not mean just overfly but can loiter for as long as our fuel holds. It means that we can hang over your country at 70,000 ft and take as many pics as we like and know that you cannot to the same against US. People can laugh at US for shooting down a claimed 'weather' balloon, but legal and war experts knows better.