A Barnstormer in Oz: A Rationalization and Extrapolation of the Split-Level Continuum, is an alternate Oz novel written by Philip José Farmer and published by Berkley Books in 1982.
Hank Stover, a stunt pilot (who does "Barnstorming") and the son of Dorothy Gale, finds himself in Oz when his plane gets lost in a green cloud over Kansas in 1923. The Oz he discovers is on the brink of civil war as he encounters Erakna, the new Wicked Witch who is waging it. The United States government is also trying to invade Oz.
Farmer's novel depends almost solely on Baum's first Oz book which took place 23 years earlier and neglects all the sequels. Dorothy made only one visit to Oz, and when Hank arrives, the Scarecrow still rules the Emerald City. Farmer also attempts explanations and analyses of the fantastic elements of Oz, including magic and talking animals.
The novel is written for adults and contains elements of sex and violence that are atypical of most Oz stories as Hank gets into a relationship with Glinda.