This is actually an insanely long list, so below is a link to the page. I suggest you check it out:


Connections:
- - Both have a world-changing destiny.
- - Both are orphans who lost their parents at a young age.
- - Both have a permanent mark of their foreheads; Aang has his arrow tattoo/Harry has is lightning scar.
- - Both are famous in their respective worlds.
- - Both try and face the darkness alone but their friends will not let them.
- - Both have several mentors throughout the narrative

Read the full list here!

Thanks to @CassiusGren for linking us to this.