The mundane explanation - there is ALWAYS a mundane "explanation" - is "mass hysteria" plus "undue influence" by the investigators.
As we see even on these forums, for many people ANY mundane explanation is preferred to any non-mundane explanation.
The ones I love are those that combine multiple mundane explanations - the two pilots were misled by Venus, the aircraft and ground radar malfunctioned, the three ground witnesses at two different locations saw the Goodyear blimp, and the ground traces were made by rutting moose. A bit of an exagerration, but not by much.
