The UFO sightings did not start in America with the 1947 sighting by Kenneth Arnold. A year earlier, waves and wave of UFOs were seen in the Scandinavian countries like Sweden, Norway, Denmark and Finland. But they were not referred to as Flying Saucers or UFOs because the terms came into existence only in 1947 and the latter in 1952 respectively, courtesy, the American Air Force.
During the Second World War, UFOs were seen all over the world, especially over the European and Far East theatre, where they were referred to by the allied pilots as Foo Fighters.
In 1946 just one year after the Second World War ended another wave of UFO sightings was witnessed, this time in Europe over the Scandinavian countries where they were called Ghost Rockets.
The Swedish government covered up the entire incident and started releasing information only 40 years later. One interesting incident happened on the night of June 9, 1946. A brilliant light streaked over Helsinki, Finland, with a smoke trail and the sound of thunder; its luminous trail persisted for ten minutes and the same incident repeated the next night, except in this case the Ghost Rocket turned and went back in the direction from which it had come which certainly ruled out the possibility of it being a natural phenomenon like meteor or asteroid.
On June 12, the Swedish Defense Staff asked military personnel to report their sightings through official channels, admitting that they had been aware of the phenomenon since May. On July 9 alone, more than 200 Ghost Rocket sightings were reported, many of them being described as tubular or spindle shaped objects flying low and slowly, with little or no sound. Soon the Swedish government established a special "ghost rocket" committee to look into the matter. A week later American Secretary of the Navy, James Forrestal, travelled to Stockholm to meet with the Swedish Secretary of War.
On August 11, 1946 more than 300 reports of strange sightings were observed in just the Stockholm area alone. Soon the Swedish newspapers started censoring most reports of ghost rockets. However, reports continued to come in from other Scandinavian countries like Norway which provided some of the best reports.
In 1984, when the Swedish Government finally opened its "ghost rocket" files, UFO researchers found more than 1,500 reports had been secretly collected during this period.
Common characteristics of these Ghost Rockets as described by both military and civilian eye witnesses were great speed, intense light frequently associated with missile, lack of sound, and approximate horizontal flight and none of these fit with any flying objects of natural origin like meteors, asteroids or comets. The interesting part was the Swedish government tried to blame the UFO sightings on Soviet Union accusing the Soviets of testing the captured German V 2 rockets. A good diversionary tactic that many people believed, but years later it came out that the Soviets had immediately moved the captured German V2 rockets to Poland.
Forty years later Swedish Air Engineer Eric Malmberg who was the secretary of Sweden's Defense Staff committee that dealt with this matter during 1946 stated that everyone on the committee including the chairman knew that these Ghost Rockets did not originate from the Soviet Union. No evidence pointed towards that. On the other hand, based on the reports acquired it appeared that some kind of a cruise missile was fired on Sweden. But the problem was no nation had sophisticated cruise missile technology in 1946. By the end of 1946 as reports of Ghost Rockets from Scandinavia began to diminish but reports of similar sightings from Hungary, Greece, Morocco and Portugal started coming in, making this a truly global phenomenon.