Sighting in Thyez, April 24, 2015

Between 10:30 and 11:00 pm, a father and his children were lying on their terrace looking at the starry sky. The father suddenly noticed a moving shadow in the sky. He described a dark shape resembling a delta wing, racing at great speed toward the south along a straight path. No particular sound was heard during the observation, which lasted 2 to 3 seconds. The witness then lost sight of it in the distance, hampered by light pollution. No other testimony was collected.

According to the investigation, such a brief sighting of a dark object could be consistent with a nocturnal bird of prey, such as an owl or eagle-owl, flying over the witness. Since the witness lives at the edge of a forest, this hypothesis is possible, but GEIPAN has nothing to support it. The witness themself thought of a stealth aircraft; however, such an aircraft is hard for radar to detect but not particularly quiet, and it usually flies at high altitude. Because there was no corroboration and the account was so brief, GEIPAN classified the case as category C, insufficient data.