This is a third-party expansion that brings the air combat action of Check Your 6! to the skies of Word War I. The book contains supplementary rules to convert the CY6! mechanics for play in the WWI era. Included are over 70 historical scenarios presented in the CY6! format. Stats and maneuver sheets for 78 British, French, and German aircraft are also provided. Note: The original Check Your 6! rulebook is required to play.