I follow the thread and only one of the flags were mentioned AFAIK.
There is an obvious flag at the start, around 0:03. Everyone noticed it, but it hardly moves so we could make no conclusions. What I did not see mentioned is the flag around 1:13. People did not notice because after 2 seconds the flag is out of the frame. It is barely visible to begin with.
Obviosly this was done in paint. No red line on the picture is based on serious data. I will try to fix the video to the flag to try to understand it's position but as far as the naked eye can see I think there is at least a 20 degree difference between the UAP trajectory and the direction the flag is facing.
This might be the make-or-break detail when it comes to the balloon explanation.