An account in Seine-et-Marne, France

On August 4, 2017 between 1:55 PM and 2:10 PM, a witness is intrigued by an object at the cruising altitude of airliners. With binoculars, the witness makes out, fixed in the sky, a vertical cylinder with the upper part (1/3 of the cylinder) red-orange, the lower part (2/3 of the cylinder) white, until a large cloud coming from the southwest hides it. Two planes pass almost directly above the observation point, one coming from the west heading east, the other coming from the south heading northwest. Once the cloud dissipates, the observed object is no longer there. The witness thinks of a drone although the object's altitude is high. No other testimony is collected. The strangeness perceived by the witness seems to lie in the object's stationary nature, its shape, and its disappearance. The stationary nature is difficult to assess. The witness indicates that the cloud came to cover the UAP; the relative movement between cloud and plane could just as well be due (at least in part) to the UAP moving toward the cloud. It is common for an airliner to appear as a cylinder or cigar without wings. The sun's illumination fairly continuously finds reflection conditions on a cylindrical or rounded surface (fuselage, aircraft nose), while reflections on the wings are certainly much stronger (larger mirror surface) but extremely fleeting (all-or-nothing). The assessment of the cylinder's verticality is entirely subjective: if the aircraft is moving in the plane containing the witness's line of sight, the fuselage appears vertical. If this plane is transverse to the line of sight, the fuselage appears horizontal. A high-altitude aircraft, with no contrail behind it, can be visible for a moment due to the reflection of sunlight on the aircraft, and become invisible a little later due to the evolution of that same reflection. And once it disappears from the naked eye, it becomes impossible to re-fix binoculars on it. It should be noted that the witness is located in a place with heavy aeronautical traffic at all altitudes (at least at that time of day), and that observing this traffic in the sky has already led him to feelings of strong strangeness that resulted in a report to GEIPAN (EMERAINVILLE (77) 05.06.2017). Since it is verified (here by analysis of the aeronautical context) that the observation itself reports nothing strange, GEIPAN does not devote more resources to identifying more precisely an aircraft hypothesis (which exact plane) given how high its probability is. Consequently, GEIPAN classifies the case as A: Aircraft.