With the released NSA documents concerning the subjects of UFOs, it seems remarkable at the low graded intelligence contents of these formerly withheld documents. There are in some references which mentioned that the incidents they were describing were "probably balloons". If we take this at face value then the objects that were subject of these documents were mis- identifications. But suppose that this term was in fact an code word, or an alternative term for something else?
Also it seems to me the NSA whilst processing the original FOIA request for a search for the documents, may of been a carefully selective in its search for such documents, and only acknowledge those of a certain quality of intelligence, for possible future release. I am sure the NSA may have specific tasks looking for such reports in there intelligence collection programs and projects throughout the NSA. But these activities would be "classifiable" in itself. I am confidence that every agency be it military or civilian has a collection program for UFO related reports which are apart of other general programs. Some of these projects use numbers rather than actual names.