Garland Greene is a convict introduced in the second half of the movie. Greene is portrayed as being a insane, mental serial killer, notably for the murder of close to thirty individuals along the eastern coast of the United States. One of his most noticeable physical features are his blue bug-like eyes.
Greene is brought to Carson City for a prison transfer aboard the plane "the Jailbird". Unknown to the guards, the plane had been hijacked by its own prisoners, led by Cyrus "The Virus" Grissom. Greene was transported from a heavy security vehicle, with numerous restraints, causing a stir among the disguised convicts posing as guards. Parolee and ex-miltary hero Cameron Poe is mutually shocked by Greene's presence on the plane. His prison friend "Baby-O" is also disturbed by Greene's murders, identifying him as "the Marietta Mangler" and that his killings made "the Manson Family look like the Partridge Family."
Shortly after escaping Carson City, Grissom orders Nathan "Diamond Dog" Jones to release Greene, whom he considers a "national treasure", praising his crimes. Diamond Dog is visibly shaken by Greene's intimidating features. Later, Greene sits next to Poe, musing about fellow prisoner Billy Bedlam's mental behavior. A while later, Poe is forced to kill Bedlam, who became aware of Poe's status as a free man. Greene deduces the aftermath and discusses the semantics of murder and insanity, much to Poe's disgust.
When the Jailbird lands at Lerner Airfield, Green separates himself from the other criminals and meets a girl playing by herself in an abandoned swimming pool. The girl invites him to play with her, but soon questions his unhealthy-looking appearance. When Greene explains there is no medicine for his condition, the girl invites him to sing "He's Got the Whole World in His Hands."
Later, when Grissom's plans to escape are foiled, he orders the Jail Bird to take off, Greene having rejoined the other prisoners, carrying a doll resembling Ken, most likely given to him by the little girl, who is last seen waving goodbye to the plane.
When the Jailbird is forced to make a landing in Las Vegas, Greene is again singing merrily "He's Got the Whole World in His Hands" during the descent. The plane eventually crashes into the Sands Hotel and Casino, Greene evades capture by the police. He is last seen playing craps at a casino, wearing a jacket and enjoying a drink, feeling lucky and his appearance looking more healthy and sane.