I think mass hysteria is too perjorative. We have a lot of suspicious data points, but then a new data point turns up (early lights were a false alert) which suggests that the data generating process may be pretty biased.
Definitively not coincidence, but there are a lot of things that could cause a pattern of reported air lights - such as a warning to be on high alert looking for them, the autumnal equinox (nights are getting much darker very quickly in Denmark right now), etc.
