Cool video i hadnt seen it before. The initial spheres could be fireballoons or whatever theyr called, they are often released in large groups. The final craft, could perhaps be a hot air balloon or some other kind of decorated balloon. It looks like it accelerates, but its not clear enough.
The thing looks similar to another sighting video some years ago, which was shot from a busy street intersection, somewhere in south america.
If u count the number of ropes in this http://www.bristolfiesta.co.uk/gallery/NG_2.jpg [Broken] and count the number of lights on the ufo (i think its 12, 13 or 14), see if they match.