Uap, UFO, Disclosure, Roswell, Radar.
Donald G. Carpenter, Lt. Colonel Edward R. Therkelson (or his obit here): Daily newspapers.com hits for various period-common UAP related phrases, between June 26, 1947-July 31, 1947. (There were none before June 26, 1947 in their database for that month.) Daily newspapers.com hits for key phrases,