The Argument for the Unidentified Flying Object Being of Extraterrestrial Origin

In Project Moon Dust, Kevin Randall is doubtful that we can form conclusions about this case. But one argument he has would lean in favor of an extraterrestrial origin for the unidentified flying object. What do you make of that argument? I'm skeptical of it. It seems more likely to me that this would have been pre-planned as an operation rather than spur of the moment. And that would point to the craft being of terrestrial origin, like some kind of secret project.