Each plane has up to 10 Modules that can be applied and tuned up for better efficiency. The more technologies you upgrade for the plane, the more Modules become available for you. Each Module improves a separate aspect of the machine, such as the engine, armor, agility, or damage. Modules have 3 levels, ranging from the most basic (Bronze) to the most beneficial (Gold). You can tune up each Module repeatedly to obtain a satisfying result. Each tune-up generates a random outcome, and if it’s higher than the current statistic, it’s automatically installed. Installing all Modules and tuning them up to a Silver or Gold status can significantly improve a plane’s performance.