Mysterious high-speed flying object recorded by UAV

This recording shows that a very mysterious white object flies directly above and below a small UAV, which is recording the scenery around Petersburg, Ontario. It was a quiet day. The sun is bright, the waves are calm, and the wind is almost invisible. This small UAV drives from the bank of the Otonabi River to the scenic train bridge. When the UAV starts flying 12 meters (36 feet) above the water, the UAV operator is right behind the UAV.