UFO Conspiracy Theories has Holes

from Discovery.com:
Keeping state secrets is difficult enough, but a conspiracy of this magnitude would involve thousands, or perhaps tens of thousands, of people in a dozen or more countries. There are plenty of (often contradictory) stories from both known and anonymous "former officials," yet not a single person has come forth with hard evidence of extraterrestrials.

Peckman and other UFO conspiracy theorists have a difficult time explaining why, exactly, all the governments of the world are so concerned about the public being aware of aliens, what the purpose of a cover-up would be.