Previous Chinese surveillance balloon incidents that occurred during the Trump administration and early under the Biden administration were not spotted by NORAD at the time, Air Force Gen. Glen VanHerck, commander of the North American Aerospace Defense Command and U.S. Northern Command, told reporters Monday. VanHerck said that U.S. intelligence made NORAD aware of the threat posed by the surveillance balloons after the fact through «additional means of collection and made us aware of those balloons that were previously approaching North America or transit in North America.»