We just produced Your a Good Man Charlie Brown. We needed to fly a kite and the director wanted it to fly out over the audience. I used 150 # Spectra fishing line (moss green) and  created a continuous loop from the back of the stage to the tech booth behind the audience. We used an inverted bicycle wheel as the drive in the booth. The stage end was passed through a double pully at the rear of the stage above a flat and then through a double pully and down to the floor. At the floor was a weight (a few pounds is all to keep the kite up when it was let go). at the weight was a single pully. The kite was attached to the loop of fishing line and the unattached line was passed through an eyelet at the top of the kite. The appearant kite "string" was a brightly colored light weight rope. Charlie Brown could pull the kite down thus raising the weight behind the flat. As he released it it would "fly" away from him across the stage. Then the operator in the tech booth would spin the wheel back and forth to advance the kite over the audience and eventually crashing it into the tree (the flat on stage). It worked very well. The fishing line is very thin. We painted it black with black magic markers. It wasn't completly invisible but the effect was well recieved.