The Red Baron Mission Builder is an expansion pack for the Red Baron World War I flight simulator and cannot be used without the original game. The Mission Builder adds a detailed mission editing program to the game and allows you to create, modify, and play user designed missions. The Mission Builder allows you to control variables such as mission region, squadron locations, aircraft types, historical aces, and squadron objectives. Virtually any historical mission can be recreated subject to limitations on the number of aircraft involved. The Mission Builder also adds 6 historical aces and 5 aircraft to the original game. The Mission Builder is supported by numerous user created missions and utilities available online.