A Barnstormer in Oz

Blurb

A Barnstormer in Oz: A Rationalization and Extrapolation of the Split-Level Continuum is a 1982 novel by Philip José Farmer and is based on the setting and characters of L. Frank Baum's The Wonderful Wizard of Oz.
The central character of the novel is Hank Stover, a pilot and the son of Dorothy Gale, who 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; he encounters Erakna, the new Wicked Witch.
Farmer takes an unusual approach to the corpus of Oz literature; he depends almost solely on Baum's original Oz book and neglects its many sequels. This "originalist" approach to the Oz mythos is rare but not unique; a few other writers have taken similar tacks, including Roger S. Baum, the great-grandson of L. Frank Baum. In Barnstormer, Dorothy has made only one visit to Oz; when Hank Stover arrives, the Scarecrow still rules the Emerald City, just as at the end of Baum's first Oz book.
Since Farmer wrote for adults rather than children, there are elements of sex and violence in Barnstormer that are not typical of the Oz literature.