What is the author’s purpose in writing this passage?

Authors use narrative prose to tell stories. This passage does just that–it tells an entertaining story about two passengers on an airplane flight.
To inform is incorrect. Authors use nonfiction passages to inform (educate) their readers about something. This passage is fiction.
To persuade is incorrect. When an author wants to persuade readers to adopt a certain stance or point of view, they often use persuasive language such as “you should…” or “you ought to…” This passage contains no persuasive language.
To describe is incorrect. When an author wants to describe something–a place, or a person, for example–he or she will use descriptive language such as adjectives or imagery. This passage does not contain such language.