This project, until recently, was stored in a folder titled "Too boring". People keep asking me about blowing balloons around with fans however, so here it is for reference.
It's difficult to blow balloons around with desk fans, as the air emitted isn't very directional. A fan tends to just swoosh the air around a bit, rather than send a purposeful blast.
To try and overcome this, two fans were modified to house a hidden airline from a compressor. Even then I think we used some fishing line on the shoot. Saved again by fishing line...