A bright light in the sky... Never seen that before? Actually, I lived near an airport so I saw bright lights in the sky all the time, it’s called a plane, or a jet, or a helicopter.
Of course, just because they "believe" they saw something doesn't mean that it wasn't a kind of mass hallucination.
But whatever it was, real or not, it was interesting as hell.
BTW, helps to keep an open mind about this stuff. Who knows what's going on.
Of course, we don't know how mass hallucinations occur or why people/children might see the same things (saucers and gray aliens in this case), but such things are not any more or less likely than REAL aliens from another dimension or star system.