The balloons are back: The origin of an object spotted floating 36,000 feet over Hawaii is unknown

• The Pentagon is tracking a high-altitude balloon spotted in Hawaiian airspace.
• The device, floating at 36,000 feet, is not a threat to civilians, the Department of Defense said.
• Three Chinese surveillance balloons were shot down across the US earlier this year.

Another mysterious balloon has been spotted over US airspace.

A high-altitude balloon, spotted floating at 36,000 feet, is being tracked by the Department of Defense after being spotted over Hawaii on April 28.