- This page refers to the tuning concept. For a list of parts in each game, see the subpages Tuning/Ace Combat X and Tuning/Ace Combat: Joint Assault.
Parts can be unlocked by completing Campaign mode missions, destroying the star targets found therein (if any) or achieving certain objectives. Parts are divided into five categories: Engine, Wing, Armor, Weapons and Cockpit. Most parts will have both beneficial and adverse effects on an aircraft: for example, a heavy armor upgrade will raise defense, while speed and mobility drop.
In Ace Combat X, the tuning options were originally limited to fictional aircraft, with the exception of the Fenrir. Joint Assault expands upon this concept, allowing all aircraft to be customized, except the 747 200B airliner, which cannot be flown or otherwise used outside the mission "Grand Flight".