 Stories of black helicopters first appeared in the 1970s, and were linked to reports of cattle mutilation.It is possible that the idea originated in Hal Lindsey's book "The Late, Great Planet Earth", published in 1970 and popular among conspiracy theorists.Lindsey theorized that the locust-like creatures referenced in the Book of Revelation in the New Testament were actually helicopters, which John had never seen and thus did not know how to describe.