doesnt really look convincing to me. I think the half speed version looks more real, and there they just look like birds swooping, maybe seagulls. Thinking maybe the first portion of the clip was actually sped up to give the appearance of speed to the objects. Could be wrong, just my hunch. Also, it seems like these objects were not a point of interest to the videographer, as he/she does not try to follow them as they go out of frame. Plus, whoever posted it to youtube disabled ratings and is monitoring commetns, red flag in my opinion.
But htnaks OP for sharing!