Hey Suzanne... This one has been asked before, and fairly recently.. Do a search within this site  on wizard of oz or witch, I think you will get lots of helpful info...

With regard to the balloon, Trinity Rep, a great company out here in Rhode Island used a balloon in their adaptation of A Christmas Carol this year, and even though they had plenty of fly space, they rolled it out onto the stage with a mechanical puppet flying horse attached to the front, although on here it sounds kind of hokey it looked beautiful, becuase of its construction of antique silk and white and gold basketry, it was definitly a sight to behold, along with some smoke underneath it and the gentle flapping of the winged horse, it appeared as if it were flying!