At [1:27](https://youtu.be/-ZJ3T7PBO6Q?t=87) of this clip from *Pearl Harbor* (2001), Japanese bombers are flying over  teenagers somewhere in Hawaii playing baseball. The  Japanese machine gunner then gestures his arms vertically, but why? He doesn`t appear to be waving as a greeting.

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/gtyVg.jpg