Sighting in Vernouillet, March 20, 2011

In the middle of the afternoon, a pilot flying a plane slightly above Dreux aerodrome saw an object ahead and made an evasive manoeuvre to avoid it. The object was shaped like a polygon with many facets, mostly black and a few green. Its diameter was estimated at 2 to 3 metres. It seemed stationary, or moving very slowly. By the time the pilot turned back, the object was gone.

The investigation concluded that it was probably a thermal balloon, also called a solar balloon, launched by amateurs. The black colour, the apparent lack of a gondola and the size all fit this explanation. However, no other example of a thermal balloon with this shape was found. The disappearance could, at a stretch, be explained by the aircraft's turbulence, which may have destabilised the balloon and made it drop quickly. GEIPAN classified the case as B, meaning probably identified.