The vast majority of the trails as already highlighted is grey waste water via the heated drain masts under the fuselage. This chemtrail believer in the US (Wyoming) regularly captures the grey waste water jettisons to delude his followers. He is too far down the conspiracy rabbit hole to reason with.
The footage due to the lighting highlights the grey waste water trail coming from the belly. Most filming gives the impression that it is emanating from the tail cone area.
Boeing 747
Boeing 747
Airbus A380
He has other examples on his YT Channel.
https://www.youtube.com/channel/UCse...IZLjUqw/videos
You can see the staining under the belly in the following image links.
https://www.airliners.net/photo/Air-...428M/1127179/L
https://www.airliners.net/photo/Thai...-642/1099785/L