At 3:57 it briefly zooms across the sky like an orb smaller and then bigger. My camera is 60 frames.

Yup, nice catch!

It is fun to observe. Sometimes when walking in the street I see them flashing. It's like my brain is recognizing these flashes of the
UFO's now.
I tought sometimes I'm filming insects but flies can't really do a vertical take of.

I'm still doubting if I filmed insects sometimes. There has to be a way to prove it when filming vertical. I'll make another one when it is more sunny in Brussels.