UFOs observed in Scandinavia, Western Europe, Turkey and North Africa between 1946 and 1948. A concentration of sightings occurred in Sweden during the summer and fall of 1946. Mysterious fireballs and Cigar-shaped UFOs constituted the majority of the reports. The objects usually travelled at altitudes between about one thousand and three thousand feet. They were variously described as travelling slower than airplanes or crossing the sky in seconds at fantastic speeds. The objects generally appeared from South or Southeast but were known to travel in all directions and to execute turns and circular manoeuvres, something no known aircraft at the time could do. Aerial explosions were frequently reported in association with ghost rockets but seemed to provide no debris. Reports of UFOs falling into lakes led to rumours that the Swedish military investigators had recovered metallic fragments which were being examined. These stories were never confirmed.
During this post-war period, it was commonly believed that the ghost rockets were secret weapons developed by the Russians who had taken over the German Rocket base at Peenemunde. Retired U.S. Air Force Lieutenant General James H. Doolittle (Of the Doolittle Raid) visited Sweden purportedly on business for the Shell Oil Company. However, the press announced that he was assisting Swedish authorities in their investigation.
In October 1946, the Swedish defence ministry issued a communiqué stating that eighty percent of the one thousand reports of ghost rockers could be attributed to natural phenomena but that radar had detected about two hundred objects “which cannot be the phenomena of nature or products of imaginations, nor can they be referred to as Swedish Airplanes”.