At minute-5:30, we see the flag behind and above Trump become horizontal, just before the shots were fired. A sniper said online the wind could have veered the bullet by 3 to 4 inches. That plus Trump turning his head at exactly the right time probably saved Trump’s life. At other times in the video, we see the flags hanging without the wind blowing.
Unedited footage: MAGA Rally in Butler, PA: Bodycam Footage BWC2-122104