The main series of games takes place in a fictionalized world populated with fictional countries with details loosely based on real-life locations, events, and wars. One of the main selling points of the series is the ability to pilot a range of aircraft that include accurate or slightly modified representations of present-day military aircraft, prototypes that never saw actual battle, and completely fictional boss-type superweapons. There are small hints of the continuity between the games, as some characters and events are referenced from one game to another.