Disc-shaped object moves at high speed at high elevation in the day time.

I was filming a flock of American White Pelicans flying high in the sky with a 12x zoom on my Galaxy S21 in "video mode". An object moves across the very narrow field of view at a seemingly higher altitude than the pelicans and at a high speed. For reference, the pelicans were gliding very slowly in the sky. There is a moment in the video where the object crosses paths with one of the pelicans and I am unable to determine whether or not exactly the object is in front of or behind the pelican. The object holds a steady speed and trajectory through the video. The object also makes a left-to-right tilt in orientation, sort of ruling out the possibility of it being a plane. There is a possibility it could be a bee, but if it were a bee wouldn't it appear much blurrier in the foreground with a 12x zoom? The other possibility is that it is a bird at a significantly higher altitude catching high speed winds, but the shape of the object does not appear to be bird-like. I did not view this with the naked eye but discovered it in my video afterward. This is all of the information I have.