Originally posted by Bentley
Superman is a rip off of Captain Marvel, original Supes didn't even fly 😬
The original weaker Superman was supposedly based on Gladiator (the novel) to some extent, with the character's name taken from either the George Bernard Shaw play "Man and Superman" or from the play's inspiration of Nietzsche's Ubermensch (Superman).
The later more powerful Superman apparently copied some of his powers like flight and uber-invulnerability from Captain Marvel, who was himself based on Superman.