National Why balloons are now in public eye — and military crosshairs President Joe Biden said Thursday that the U.S. is updating its guidelines for monitoring and reacting to unknown aerial objects. FILE – A high altitude balloon floats over Billings, Mont., Feb. 1, 2023. (Larry Mayer/The Billings Gazette via AP, File) AP WASHINGTON (AP) — Wafting across the United States and into the attention of an alarmed national and global public, a giant Chinese balloon has changed Americans’ awareness of all the stuff floating in the air and how defense officials watch for it and respond. President Joe Biden…