Ozoplaning with the Wizard of Oz by Ruth Plumly Thompson (not L. Frank Baum, as it was written after his death) is the 33rd book in the Oz series. The story revolves around the Wizard of Oz introducing ozoplanes, futuristic aircraft, to Oz. Dorothy, the Wizard, and several familiar characters embark on an aerial adventure, encountering new lands and characters, including the mysterious realm of Stratovania, while overcoming challenges to return safely to the Emerald City.