The five cerulean five-pointed stars arranged in an X pattern centered in the white band represent the five nations of the former Federal Republic of Central America (El Salvador, Costa Rica, Nicaragua, Honduras, and Guatemala) and the hope that the nations may form a union again.
Wind Deflectors let you enjoy cool, fresh air without all the noise and swirling winds, so you don't have to be so quick to crank up the air conditioner. Plus, deflectors improve your vehicle's open-window aerodynamics, cutting down on drag for a more efficient ride.
How does wind produce sounds? I know the basic answer, that the movement of air sets things vibrating which makes noise, but I don't know the specifics. For example, if the wind is blowing hard, you can often hear the wind howling at a certain pitch. This seems to be dependent on velocity because the harder the wind blows, the higher the pitch is.