Could Superman always fly?

No he couldn't always fly, when he first debuted he jumped really high.

When he first débuted in Action Comics #1 way back in 1938, Superman couldn't fly at all — instead, he could jump the wonderfully specific height of 1/8th of a mile. His ability to fly would first appear in Superman cartoons and Radio plays, before he picked it up in the comics for the first time in 1941.

i think it would be 5

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.