Originally posted by DigiMark007
Speed can be:
A. Travel/Flight speed
B. Reaction Time
...presumably, Superman and others can travel over the speed of light (given how fast he leaves our solar system and travels between planets, it would be silly if he couldn't). But their reflexes are nowhere near, say Flash. Or even someone like Quicksilver, who can only reach maybe Mach 5 in travel speed.
Writers are notorious for not specifying what they mean exactly, and sometimes flight speed can be used like reaction time (i.e. speedblitz in fights).
Interestingly enough, in the average human, reaction time is roughly equal to running speed (around 20mph). Flight speed, however, is a whole other ballgame which (for obvious reasons) is hard to figure compared to reflex/agility/running speed.
Seems to me, though, if a character can run/fly at, say, Mach 100, their reaction/reflex speed should be comparable. Otherwise, they could not perceive/respond effectively when at that speed.
(I'd read somewhere once that when fighter pilots are flying close to the ground, they are moving so fast that by the time their eye/brain registers a landmark, they're already like a half-mile past it).