This assumption was made by General Glen van Herck.

The American armed forces do not completely exclude the version of the extraterrestrial origin of the flying objects shot down over the territory of the United States in recent days. This was stated to reporters by the head of the North American Joint Aerospace Defense Command (NORAD) and the US Northern Command, General Glen Van Herk.

“I will let the intelligence community and counterintelligence find out. I'm not ruling anything out at this point," he said.

Glen Van Herk also noted that the US military currently cannot say for sure, "due to what these aircraft could stay in the air." “I won't characterize them as balloons. We don’t just call them objects,” added the head of NORAD.