Who cares if they are mundane or non mundane. The question is: what are they?
Forgive me if I seem a little stupid today (I have a cold), but isn't part of the reason that these reports (barring Rendlesham) are the top ten reports is because
no satisfactory mundane explanations have yet been found? (the other reason being that they most closely fit a cognitive bias towards alien visitation).
So clearly we can't give you specific answers. Until satisfactory explanations are found, mundane or otherwise, these reports remain unexplained, cause unknown. Even the documentary itself, despite suggesting alien visitation, repeatedly says we don't know what happened or what these reported sightings are. So, until things change, we stay with the null hypothesis that has remained unfalsified for so long: there is a mundane explanation.
It's worth bearing in mind that the reason the documentary was made and you're here asking the question is precisely because
the evidence, such as it is, is equivocal.
You might as well ask us for mundane explanations for all the greatest unsolved murder mysteries because you think they could have been done by <insert favorite exotic being here>.
If you want speculation, there are plenty of forums full of speculation, from conspiracy theories to Earth spirits, inter-dimensional entities, aliens, God, mass hallucination, etc. Who knows, we may even find that aliens have visited and these reports were nothing to do with them
Personally, I find the alien visitation hypothesis unsatisfactory because (apart from the overwhelming pragmatic physical considerations) there are too few reports for which satisfactory mundane explanations haven't been found, too little consistency between those reports, and too little supporting evidence in general. But that's just me - I'd love it if we were being visited by aliens who wished us no harm - who wouldn't?