The Airplane series consists of five airplane story games made by Ponchokings.
In chronological order, Airplane 3 is the first game about Ronald( in human form) hijacking a plane and the army sets off to rescue. Airplane is set after Ronald's transformation into an evil monster. Airplane 2 is a sequel to Airplane, and Airplane 4: One Last Flight, is a sequel to Airplane 2.
Cruise takes place between Airplane 3 and Airplane.
The three sequels after Airplane 3 assumed that Ronald was not befriended by the players in the bad or secret ending and revived into a monster by the evil skeleton.
Castle is not in the Airplane series and is not related to the Airplane plot although it is also made by Ponchokings.