Both of them were sons of European Jewish immigrants and they used that influence very heavily when they created the big blue Boy Scout.
One myth that Superman was based on is the Gollum from Prague which was a clay monster created by rabbis to defend the Jews from their enemies in Europe.
Also, the man of steel is based on pretty blunt metaphor for Moses. Little baby Supes escaped a dying planet on a rocket through space is very similar to how baby Moses escaped the wrath of the Pharaoh in a basket on the Nile river.
Also, His Kryptonian name when spelt in Hebrew is קל-אל which can be translated into English as the voice of God, a phrase used to allude to Hebrew prophets.
Despite being sold to the giant faceless cooperation known as DC Comics, the mainstream version of Superman’s pantheon has always remained within this Jewish lore and the character took an active stance against discrimination.
Some of the earliest enemies the last son of Krypton fought were the members of the Klu Klux Klan and Nazi Germany. Superman fought the KKK back when the KKK was a legitimate political voice in the United States and Supes entered WWII to fight the Nazis back when the United States was maintaining its neutrality in the European conflict.
It was through these adventures that the American people became so attached to the character.
The Superman that we all know and love from the comics comes into conflict with Director Zach Snyder and his iteration of Superman in the film Man of Steel.
Snyder was trying to create a more passive superman with plenty of blunt references to Jesus. Superman flies around in space in a cross pose, goes to church to get guidance and is 33 years-old in the film when he realizes his powers, the age Jesus was crucified.
More importantly, Snyder wrote a character that is not actively embracing his powers to help people. Sure Superman can save a bus full of children that crashed into a river but only if he is on it at the time of the crash. Similar to how Jesus cures the sick and feeds the hungry but only subjectively.
This passive version of the superhero is really uncomfortable to watch because it is so out of touch from the character’s origins. We are watching a film about things happening to Superman so it is weird to watch a character that is so powerful be powerless in almost every scene.
Snyder has directed three films starring this passive powerless Jesus Superman, Man of Steel; Batman v Superman and Justice League. All three of these films failed with the critics but it wasn’t until Justice League did the franchise fail in the box office. Since Hollywood really only cares about the financial bottom line, it seems Justice League will be the beginning of the end for this Batman Superman team up franchise.
Hopefully, the big shots that make movies will learn from this mistake and one day give us a film about the hero in blue that has inspired generations.