Nerys Myk wrote:
Flash has an aura around his body that protects him from the side effects of moving at great speeds.
Superman's suit, in some incarnations, is from Krypton and is just as invulnerable as he is. In others, Superman's body projects an energy field that contributes to his seeming invulnerability which makes his suit virtually indestructible. His cape, which is out side of the field, tended to get shredded. Currently Superman is pretty tough but uses his cape and Kryptonian armor to make himself invulnerable.
You might say Superman has a built in warp drive and deflector shields. Superman still makes more sense than Flash. Superman is strong and can run really fast. The Flash is not strong, but still he can run very fast. The Flash does not have super-hearing, so if someone an ordinary human could sneak up behind the Flash, and hit him on the head from behind with a two-by-four, he could knock him out. The Flash can only dodge something that he is aware of, his one power is speed.