When the Wizard's balloon is lifted without Dorothy inside it so she could return to Kansas with him, there are some minor glitches in this scene that are not logical. First, I doubt Toto would have been distracted by a cat that was way off in a crowd being held by a woman. Also, when the Wizard says he can't return because he doesn't know how it works, there are sandbags around the basket that he could have clearly used to land the balloon again. And then when Glinda appears in the bubble, the scarecrow says "Here is somebody that can help you." That does not follow logic, since the scarecrow never met Glinda on their way to Oz, so he obviously would have no idea who she was, or what the bubble had inside it.