Summary: Brief overview of U.S. Air Force Project Grudge.
In February, 1949, Project Sign came to an end, and with it the Air Force's objective attitude toward UFOs. The final report of Project Sign was decidedly skeptical towards the extraterrestrial origin hypothesis for the origin of UFOs, reflecting a shift towards explaining all sightings as misidentifications of natural phenomena.
Secretly, however, the Air Force had merely changed the name of the project to Project Grudge. The new name reflected the change in policy towards UFOs. This change in policy by the Air Force brought with it a campaign of characterizing those who believed UFOs were extraterrestrial as "kooks". Sidney Shallet, a writer for the Saturday Evening Post asked the Air Force for help in writing an article about "flying saucers". The Air Force had a policy of refusing such requests, but when they found that Shallet's article was to be of a debunking nature, they agreed to help him. Shallet spent two months researching the subject, and then wrote a two-part article entitled What You Can Believe About Flying Saucers.
This article and a press release by the Air Force reflected the new public view of the Air Force that "flying saucers" didn't exist, that they could all be explained, and that the "believers" were "kooks". However, insiders knew that the Air Force was still actively engaged in researching UFOs, and this contradictory behavior led many to believe that the Air Force was hiding what it really knew about UFOs.