In Advance Wars, a Fighter is an air unit that can only attack other air units and come at a cost of 20,000G.
Aside from other Stealth Fighters, Fighters are the only units that can attack hidden Stealth Fighters. Fighters usually do 7-10 damage to air units, unless it is another Fighter unit.
Fighters are very powerful, and it may be useful to have one on standby in case the opponent creates an airborne unit. However, Fighters should not be high on your priority list unless the map you are on puts much emphasis on air combat, particularly on maps that involve Eagle, Tasha and Waylon in command.
Fighters are also useful for taking on Bombers, which deal massive damage to Ground and Naval units. One attack from a Fighter unit at full health will pretty much abort that Bomber's attack run!
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