Note to CNN — balloons cannot reach 60 miles; (CNN) Exclusive: US developed method to track China’s spy balloon fleet within last year, sources say. 

(CNN) Exclusive: US developed method to track China’s spy balloon fleet within last year, sources say.  Quoting,

But the new method is important because the balloons are extremely difficult to track without it – they are slow-moving and can fly extremely high, in some cases as high as much as 60 miles up,

This error appears to be propagation of a typo in a government report.

For theoretical and practical reasons, the limit is close to 170,000 feet, 32 miles.

The world record is held by NASA “Big 60”.