[mdta]

I was at a presentation years back given by Martin Lambie-Nairn about various TV branding work, and I remember him saying a problem they had filming the idents was the balloon would never fly in the direction they wanted and in some of the later idents the balloon was digitally inserted.

I'd like to think today's tech would make this less of a problem.  Have a drone camera flying around the balloon.  No limited reels of film, in a big clunky camera, attached to a helicopter following along.  Film much more footage than you need, and make minor adjustments to move the balloon, and then edit it down to the perfect shots.