According to the San Diego Zoo, butterflies fly by moving their wings in a figure-eight motion. The wings of a butterfly are made of a thin layer of protein called "chitin." This is the same protein that makes up the butterfly's outer-body shell. Butterflies also have a complex system of veins that help circulate blood to their wings, which gives them the ability to move their wings quickly.
HowStuffWorks states that a butterfly's ability to fly depends heavily on the weather. The wings of a butterfly are extremely delicate, and butterflies have no way to repair wing damage. This is why it is uncommon to see butterflies when it is raining or there are strong winds – these types of weather can prove harmful to their wings.
Butterflies prefer a body temperature of 82 degrees Fahrenheit, according to HowStuffWorks. This is because butterflies are unable to move the muscles in their wings if their internal body temperature is too low. Since cool breezes can drop a butterfly's body temperature quickly, most butterflies only fly in short bursts before they land in a sunny spot to warm up again. Butterflies often use their wings to reflect light onto their bodies to warm up more efficiently.