Chinese Spy Balloons: Why balloons and where else have they shown up?

 What China’s Military Balloons Show About Its Spying Ambitions 

China Sends Spy Balloons Over Military Sites Worldwide, U.S. Officials Say - The New York Times (nytimes.com)

Undetected Chinese spy balloon flights are not an 'intelligence failure,' Pentagon says (nbcnews.com) 

Why the Chinese Spy Balloon is a Huge Embarrassment for Beijing (newsweek.com)

Spy Balloon Signaled China's Displeasure Over Three Issues: Stavridis (newsweek.com)