Both Red Tornado and the lil' kid from Avatar the Last Airbender both have those arrows on their heads. Why? Does that symbol mean air or something?
in Aang's case the blue arrow tattoos are the flow of chakra within him, as the Airbenders were very spiritual and mapped out the body's chi paths. Air flows the easiest, after all.
With Red Tornado , he is/was the host for an air elemental , so it's apt that he get a big arrow on his head. That, and it shows newbie JLAers which way the batteries go in