UFO conspiracy theories

Some conspiracy theories argue that various governments and politicians globally, in particular the United States government, are suppressing evidence that unidentified flying objects (UFO) are controlled by an extraterrestrial or "non-human" intelligence, or built using alien technology. Since the 1980s, such conspiracy theories often argue that world governments are in communication or cooperation with extraterrestrials, and some claim that the governments are explicitly allowing cattle mutilation and alien abduction.

According to the Committee for Skeptical Inquiry little or no evidence exists to support them despite significant research on the subject by non-governmental scientific agencies.