Digital Combat Simulator or DCS is a combat flight simulation game developed primarily by Eagle Dynamics and The Fighter Collection. Several labels are used when referring to the DCS line of simulation products: DCS World Modules and Campaigns. DCS World is a free-to-play game that includes two free aircraft and two free maps. Modules are downloadable content that expand the game with add-on aircraft maps and other content. Campaigns are scripted sets of missions. Modules and campaigns are produced by Eagle Dynamics as well as third-parties.