Oh, I didnt realize that there were two campaigns.
People are getting the wording mixed up here with regards to what comes with the game. There is career mode, which is where the missions are generated by the game based on the type of aircraft and for which squadron you are flying. Career mode covers the time period from late 1916 to the Armistice.
Campaign mode is any of the static, non-branching campaigns, including Du Doch Nicht, St. Mihiel, and Hat in The Ring. All of them currently take place in 1918.