Turn your eyes skyward during World War I, and you'll discover that planes weren't alone in the skies. Drachens, the enormous floating leviathans of the air, were used as observation platforms and even for barrages. In response, the Le Prieur rockets introduced in April 1916 were designed to bring them down!
The balloons were so difficult to destroy, even using Le Prieur rockets, that it required the pilot to head directly into the target while they fired. The electric switch had to be triggered very close to the Drachen, and if they happened to ignite the gases holding the balloon aloft, the plane could be caught in the blast.
These ace pilots came to be known as "Balloon Busters." Each Balloon Buster expansion set adds one spectacular Drachen model, and an additional plane model for use with Wings of War.
The Balloon Buster expansion sets are not a complete game. A copy of at least Famous Aces, Watch your Back!, Burning Drachens, or WWI Deluxe is required to play.