Case file · Sighting

O'Hare Airport

United Airlines staff reported a disc hovering over a gate.

2006 CE · 41.98, -87.90 · status: unexplained

The sceptical view

The FAA logged it and cited a weather (hole-punch cloud) explanation, which witnesses dispute.

Credible airport staff, no instruments. Ordinary candidates exist, but none matches every description, so the case stays genuinely open.

Explanation	Weight	Why
Something known, misidentified	30%	A dark, silent object hovering under a low overcast and then rising out of sight fits a lost balloon or a large bird seen against cloud, with no radar return because it was too small.
Genuinely anomalous	23%	About a dozen employees independently described a sharply defined disc that punched through cloud; no ordinary explanation fits every detail.
Perception, memory or mind	16%	The witnesses were near each other and talking; the reported hole in the clouds may have been inferred after the object vanished.
A known natural phenomenon	12%	The FAA blamed a weather phenomenon, but a hole-punch cloud needs supercooled cloud, unlikely in a mild 1,900-ft overcast that afternoon, which weakens that explanation.
A poorly understood natural phenomenon	8%	An unusual local cloud or light effect cannot be ruled out.
Secret human technology	6%	A drone over a major airport in 2006 would have been unusual and dangerous.
A hoax or fabrication	5%	The witnesses were airline staff with nothing to gain, but no photograph survives.

Official position: The FAA logged the report, found no radar return and attributed it to weather.