You mean S-foils? Well here ya go!
Historically, S-foils had been developed to address overheating issues on wing-based starfighters. Because of the proximity of engines and weapons systems to narrow wiring that fit inside the thin wings, an excess of heat could cause mechanical meltdowns that would be devastating to the capacity of the fighters to function. S-foils like those seen on a number of Republic starfighter models during the Clone Wars held radiator panels that dispersed heat and cooled the interior mechanisms of the ships. S-foils were used when stress was being put on a ship's systems, usually when it was traveling at high speeds or locked in a dogfight.
Stabilization was a key issue, especially with larger craft. For shuttles, which were often used to transport dignitaries or sensitive cargo, maintaining stability in flight was pivotal. Large folding wings served to reduce turbulence and protect the craft's contents.