Measure and cut a 30-foot wide by 8-foot high piece of sky blue felt. Paint white clouds or cut out white felt cloud pieces and glue them randomly on the front of the large felt piece. You now have your sky. Flip the large felt piece upside down. Glue four 8-foot tall PVC pipes at 10-foot intervals on the back of the large felt piece.
Measure and cut a 4-foot long by 1-foot wide maple plank. Measure out and mark 6 inches from the front side -- all the way up the plank. Leave this 6 inch space alone. Paint the remaining space blue and white. Once erected, this piece will have the illusion of a broom stick floating in the air.
Paint four 3-foot tall stainless steel tubes blue and white. Paint the tubes to blend in with the background -- you will see why in later steps.
Bracket the plank to the four stainless steel tubes. Insert wide foot holders onto the bottom of each tube to keep them safe and secure while standing upright.
Glue 12-inch strands of wicker off the tail end of the wood plank to give it the illusion of a broomstick.
Stand the plank -- or broomstick -- on its legs. Position the plank so the unpainted wood side is facing the audience. Ask the actor playing the Wicked Witch to sit on the center of the plank.
Instruct four stagehands to carefully lift the large blue felt piece. Each stagehand should be holding a PVC pipe. Have the stagehands back together -- forming a circle with their backs facing each other -- 2 feet behind the actor and broomstick. Enclose the circle until the felt is an 8-foot high, 10-foot wide cylinder.
Tell the stagehands to step uniformly to the right in a circle. The background -- or sky -- will rotate as a result. From an audience point of view, the Wicked Witch looks like she is flying.