Since 1875, the United States has seen countless reports of unidentified flying objects. These reports peaked in July 1952. That is when the Washington DC incident, known as "the Big Flap", happened. The incident was so shocking that several US generals shut down the Air Force s Unidentified Flying Objects Research Project, the Grudge Project, and replaced the Blue Book project in March 1952. The Blue Book Project studied unidentified flying objects for more than a decade, and finally in 1969 the Blue Book Project ended with a detailed report. The full report is now available on the FBI and National Archives website. But this article deals with an important and deleted part of this project that is not in the final report of the blue book project.