When the vid first starts, I immediately thought " airplane with exhaust plumes lit up by setting/rising sun".. until it gets a bit deeper into the
footage.
Then in the slow-mo, you can see what is very possibly wing tip lights flashing...
But then the whole front of the object begins to light up and flicker and flash..
This is either an airplane or it is something else.. If it is an airplane, can anyone explain how the object flashes in this manner?
Unfortunately the poster of the vid has not left any further details.. i have posted a comment to try to get more info...
As it says in the video, it was before sunrise, so as the time went by the plane started being illuminated by the rising sun, making it look like a
very bright object against the darker sky, the opposite of what happens at the setting sun, when those objects get darker.
I take it perhaps, the 'plane is heading Easterly
and you are videoing from a more southerly
direction and the 'plane could be unpainted,
and making it very bright eventually.