Did you ever wonder this? I mean these guys and gals are Super Heroes. They dress in spandex suits with mask and fancy boots with colors that would not make the runway shows. They can run and fly faster than anyone can imagine. They have special powers that can knock down walls and carry cars and stop bullets without getting a tear in their tight uniforms.
Yet why the capes?
Capes were produced to protect against high intensity weather. The cape is any sleeveless outer garment, such as a poncho, but usually it is a long garment that covers only the back half of the wearer, fastening around the neck.
Capes were common in medieval Europe, especially when combined with a hood in the chaperon, and have had periodic returns to fashion, for example, in nineteenth century Europe. Capes remain in regular use as rain wear in various military units and police forces.
The fashion cape does not cover the front to any appreciable degree. In raingear, a cape is usually a long and roomy protective garment worn to keep one dry in the rain.
In full evening dress, ladies frequently use the cape as a fashion statement, or to protect the wearer or the fine fabrics of their eveningwear from the elements, especially where a coat would crush—or hide—the garment. These capes may be short (over the shoulders or to the waist) or a full-length cloak. Capes are still authorized as an alternative to the more utilitarian trench coat for U.S. Army officers in mess dress, formal evening uniform.
In modern times, comic book superheroes, such as Superman, Batman, and Thor are often described as wearing "capes" or "opera capes", although most of these are long enough to count as opera cloaks.
So why does a Super Hero need to wear a cape?
As they fly through the sky do they fear their Super Hero costume will get wet? Should they have a hat to keep the rain out of their mask? Maybe something like a bike helmet?
Not all Super Heroes wear capes. The Flash doesn’t wear a cape but that is understandable because he runs so fast it would probably shred. The Green Lantern doesn’t wear a cape and who knows why?
But the biggest Super Heroes “Superman” and “Batman” are recognizable by their capes. I can’t figure how long it takes to get out of the Clark Kent or Bruce Wayne cloths and get into their skintight wetsuits uniforms with their logos on their chest so everyone would know who they are, then have to put on a cape.
Now Batman and Boy Wonder could get their capes caught in the Bat mobile or Superman could get tangled in the swirl of flying at super speed, they keep wearing them.
Maybe it is just a fashion statement but I don’t see the Hulk wearing a cape.