Looks like someone released many white balloons… some in clusters. They behave as if the air currents easily effect their course. UFO craft usually follow a 'less' erratic course over such short distances.
Just found your site, I think it is very cool. However, this video to me looks like a group of balloons floating away, you can see how they are grouped together and are bobbing around as if all tied upon a string. The ones around it may be the same. It is fun to wonder though.