When I first saw The Last Airbender, starting out of sequence, from Earth, probably the episode of the Face Stealer, I was immediately taken in. The characters, the cliffhangers, the weird animals and the world building. The movements were all martial-artsy. But most of all, the style of animation was what gets to you. Isn't that what it's known for, after all? An American cartoon drawn in the Japanese style? Naruto was blamed for "the death of Toonami" and hugely unpopular, while Avatar: The Last Airbender is acclaimed as the best animated series in decades. But they have so many similarities and I'm wondering if they have some connection. And this connection if it exists, would be one of lightning, orange jumpsuits and scarred faces.
The 5th element
I think the most notable similarity in the 2 cartoons is the use of elements to delare the different peoples and political systems of their worlds. However, how common would it be to use the law of elements? I might as well compare Avatar to Pokemon by that logic. But the thing here is that they both use elements to desribe politics. Yet, they're not exactly the same. Naruto was FROM the Konoha, a village in the land of Fire, while Aang fought AGAINST the Fire Nation. In Avatar, there were cultural differences between the peoples, (such as Fire Nation gathering under the banner of it's Lord and striving to take everyone over, Earth Kingdom presumably being stable and economically well off, under it's King or emperor, the Water Tribe forming it's familly bonds and Air Nomads wandering, living in temples and dying,) while all the sects in Naruto pretty much had the same political system, except for their use of resources and economy.
Apart from the traditional 4 elements of Water, Wind/Air, Fire and Earth, Naruto recognizes a 5th, that of lightning. Now, the Chinese Zodiacs recognize different metals and wood as elements, but lightning (although used in other places) is not one of the regular elements, and is used by Kakashi and Sasuke for the speial move Chidori. Avatar too recognizes this element, a little later in the show, I think by the last episode of the first season, first used by Azula. As explained by Zuko's uncle Iro, it's "refined fire", and not a separate element, but they're both present together.
Another thing about elements that they both use, is sand. Gaara of the Sand village, and later it's Kazekage, could manipulate sand, and was a huge deal. But his attribute is wind, and would be equivalent to what is an "air bender" in Avatar. Sand is light and easily lifted by the air, and how would you recognize winds, essentially energy, if not for particle matter? You may remember in one of the episodes of Earth, Aang finds a library in the desert, and Abu the Air Buffalo gets kidnapped. The people who kidnap Abu are sand benders and where lothes not too different from Gaara's buddies, but they both also reflect actual clothing used by actual sand people.
The two main characters both wear orange, Aang a little more so than at least what Naruto wears in Shippuden. They both have insignia on their forehead representing where they come from. In Aang's case, he's the last of the Air Nomads and is therefore unique, and also the only person with an arrow tattoo on his head. Everyone in Naruto has a headband. But both the arrow and the spiral "leaf" serve the same purpose. One character has hair and the other one is bald. Speaking of the arrow tattoo, which lights up when Aang goes into the "Avatar state", Naruto reaches a "Sage Mode" that's close to it, but way later.
Both of them have the orange colour in common with Goku from Dragonball. In fact, Aang's stick makes him more of a Goku than a Naruto, (and Naruto's Super Saiyan hair makes him a Goku) They also share other character stereotypes or "stock characters" with DB. Both Naruto and Aang surround themselves with a group. Now you can't compare Sokka to Sasuke, exept for their names, beause one's a badass and the other is a joke, but Sakura and Katara may have something in common. But all anime have certain recurring characters. A promiscuous monk, like Miroku. The funny old man who turns out to be the strongest of them all, (Roshi, Iro, Jiraiya) a friendly girl sidekick who is the first to discover the main character (Bulma, Sakura, Katara) and is a healer, but that comes from sword and sorery too. There's also the strong rival, (Sasuke, Azula/Zuko) who is not always the same in DB, though Yamcha, Kuririn, Tien and Picollo Jr have all played that type of thing, and Vegeta even more so, for longer. Vegeta may have lent that haircut to Sasuke.
But, the Sasuke/Azula/Zuko comparison is a little stronger than mere rivals. Zuko's eye, what's the deal with that? It's just one damaged eye, with a story behind it, a FAMILY HISTORY, and it's comparable to two people in Naruto. Kakashi, the one eyed ninja also carries Sasuke's family trait, the "Sharin gan" in one eye, his damaged eye. Sasuke has it in both. Kakashi and Sasuke are teacher and student, and Kakashi passes on his Chidori to Sasuke, which is lightning, like what Azula uses. Zuko himself had a mentor for most of the story, his uncle Iro, who helps Zuko with his lightning. Groups in Naruto work in 4s, until Naruto's team loses Sasuke, while Aang starts with 3, until Toph, the blind badass, makes a fourth.
Other than appearance, the core of the title characters have something in common too. Naruto is the self titled "number one, knucklehead, hyperactive" ninja, the one who always barks first, driven by emotion and loyalty, and optimism. Although Aang is over a 100 years old, he too is a kid at heart. When Aang starts out on his journey, he likes to try stunts in the air, play with balls made of air and he sets up his route so he can travel to exotic places.
Line of succession
Both the Avatar and the Kages, be it Hokage, Kazekage or Raikage, are lines of succession. Naruto aims to be a Hokage, his father is a Hokage and he befriends Konohamaru, grandson of the Third Hokage (who he also annoys the heck out of). In his spirit state, Avatar Aang could speak with the old Hoka- pardon me, Avatars. Jiraiya teaches Naruto something about the same, and writes a book of encrypted secrets, which may have been passed on to Naruto.
Volcano scene (non-Naruto related)
In Dragon Ball, there's an episode where the "Z warriors", the B- listers of the team, Yamcha, Kuririn, Tien and Chiaotzu have to save a village from a lava flow. How they did it without any powers, I cannot remember. You can see the same thing in Avatar, except it's all of them, Aang, Katara and Sokka, maybe Toph. 3 benders and a non-bender, but Sokka definitely plays a central role here. Come to think of it, Aang kinda looks like Kuririn. A LOT actually.
But how do we judge this? Dragon Ball and even Thundercats had obvious references to Superman. The cover of Death of (Ultimate) Peter Parker mirrored Death of Superman, in homage. The Fantastic Four are based on the elements, and Superman may look like Jesus. So can any work of fiction then be completely free of influences by other sources? but how far should something be allowed to copy off another?