Airline Tycoon series
Airline Tycoon is a series of games developed by Spellbound. The first title of the series was Airline Tycoon, released in 1998, in German only. Airline Tycoon First Class, released in 2001, was the first title in the series released in English. The consecutive releases between Airline Tycoon and Airline Tycoon Deluxe are rather expansions than new versions, but they are stand-alone games, though.