Exactly insects. They're flying insects. They act like insects, look like insects. They are insects. Put a camera in any field and you'll get insects flying past. Maybe everyone involved doesn't spend much time in the countryside. Otherwise they wouldn't be making fools of themselves like this. I've often stood on a field on a hot summer's day. When there's no wind and it's quiet you can hear them buzzing past but you can hardly see them.
I suspect modern HD cameras can pick them up in a way that previous cameras were incapable of.
Unless of course they really are nano UFOs sent to monitor us