The film series took many elements from the show. The following is a list of elements taken from the original animated series which are otherwise omitted or changed, e.g. the Avatar State. The inclusion in the movie may not follow the same order as the series - see the synopsis section of The Last Airbender page to see how these elements were incorporated into its own story and direction. For special cases, differences are mentioned only to clarify or qualify the statements of included elements. Note that the novelization for the first movie has additional elements but were omitted or revised in the final cut, e.g. Aang crushed some the Fire Nation fleet.
- The main characters are Aang, Katara, and Sokka, for the hero side, Zuko and Iroh for the anti-hero side, and Zhao and Ozai for the villain side.
- The scenes for Suki and her Kyoshi Warriors were shot but moved to the sequel, although we can see them in behind-the-scenes featurettes, glimpses of them in the deleted scenes, and their story was still in the novelization. Their costumes and weapons were similar but without the face paint. Rather than protecting the Kyoshi Island from intruders, they took over the roles for Jet and the Freedom Fighters.
- Sokka's characterization and depiction was closer to the episodes "Jet" and possibly "Bato of the Water Tribe". He had some funny moments but more serious, level-headed, and responsible. In a deleted scene, he was shown to be an adept fighter, which suggested why Pakku accepted Sokka's offer to guard Yue at all times.
- Aang's arrow was included but as form of an intricate tattoo, received after achieving the Master status. In the movie, Aang achieved his Master status after being able to meditate for long periods of time without losing focus.
- Most of name pronunciation were kept except for Aang (ɑːŋ), Sokka (Sōka), Iroh (ɪˈroʊ), Avatar (ɑvɑtɑr), and Agni kī Duel (अग्नि की डूएल). Note that Shyamalan pronounced Toph the same as the series in the audio of the roundtable discussion.
- Elemental bendings and its associated martial arts forms were kept with some key changes:
- Firebenders cannot generate their own fire but must bend fire from nearby sources, except for high-level firebenders like Iroh.
- Airbending is more like Wind Release from Naruto, as suggested with Aang's deleted line that is still in the novelization: "We airbenders learn to feel the energy behind the wind, not just the breeze on our skin. It's all about controlling energy". Thus, airbenders need to redirect wind energy to move air unless they are high-level airbenders like Aang.
- Benders were a chosen few, i.e. "The powers to control the elements are bestowed upon a chosen few". Thus, non-benders are more prominent in the movie, engaging in fights with weapons or hand-to-hand combat.
- A new composite character, the Dragon Spirit, took over the roles originally played by Avatar Roku, Fang, Koh, and Guru Pathik.
- As for hybrid animals, Momo and Appa, are depicted in the film, the latter without its arrow. Tiger seals are mentioned, while komodo rhinos are depicted without the horns.
- The "Yip Yip" for Appa was included but only heard once in the movie. For the novelization, it was used several times.
- As in the animated series, only the Fire Nation had machines, which gave them a tactical advantage over the other nations. The machines depicted in the movie include the warship, the tank, the portable spinning drills, and the fire cannons.
The Boy in the Iceberg
- Katara was practicing waterbending but ended up soaking Sokka. Katara was accompanying Sokka who was hunting for food.
- The glowing icy sphere revealed itself in the presence of Katara, emerging from an icy plains rather than in revealed from in iceberg. Seeing a silhouette of a person inside, Katara wanted to help the person and chops at the sphere with Sokka's boomerang (instead of a club), even though Sokka warned her not to. The ice breaks, and shots a bright column of light into the sky. The resulting crater revealed Aang and Appa lying unconscious.
- Zuko also saw the beam of light from sphere and alerted his uncle.
- In the novelization, Aang was playing games with stones with the children escorted into the igloo, while the Fire Nation was outside. This was in reference to the series where Aang was playing with children in the Water Tribe and bonded with them.
- Zuko's combat training on his ship with his men.
The Avatar Returns
- Katara realized that Aang has been in the ice for a hundred years.
- Zuko demanded the Southern Water Tribe villagers to "bring him all the elderly" as he was still under the impression that the Avatar was physically 100+ years old.
- Aang surrendered to Zuko, in exchange for not hurting the others. He was taken to Zuko's ship.
- Sokka and Katara rode on Appa to catch up with Zuko's ship, after getting Kanna's blessing.
- Aang escaped and evaded Zuko and the other firebenders to the surface of the ship with his airbending skills.
- Aang saw Appa landing on the cliff in the series. He was then reunited with Appa and others and proceeded to the Southern Air Temple.
- Zuko was upset that he underestimated Aang, which allowed Aang to escape his grasp.
- Aang must master the other elements according to the Avatar Cycle: air, water, earth, and fire.
- It was established that Aang, Sokka and Katara must travel to the Northern Water Tribe to master waterbending.
The Southern Air Temple
- Aang met with a winged lemur, later named it Momo.
- Aang found out about the Air Nomad genocide after seeing the skeletal remains, and recognized the remains of Monk Gyatso with his necklace. He went emotional and entered the Spirit World, as opposed to entered the Avatar State as in the series.
- The statues of past Avatars were featured. The first statue was of Avatar Roku, his previous incarnation.
- Zhao's first meeting with Zuko and Iroh in the story is when he invited Zuko and Iroh to have lunch with him on this ship, as opposed to tea from the series.
The Warriors of Kyoshi
- Avatar Kyoshi was Aang's incarnation two lifetimes ago. Her statue was featured.
- The Kyoshi Warriors were originally in the movie but moved into the sequel. Their uniforms and weapons were similar, however they had no face paint.
- In a village, earthbenders were rounded into a prison and earthbending was forbidden.
- An unnamed earthbending boy (originally played by Haru) was apprehended for earthbending. In the prison, he was reunited with his unnamed earthbending father (originally played by Tyro).
- The imprisoned earthbenders were non-responsive when Aang (originally played by Katara) tried to inspire them to rise and fight back. They only fought back after the boy threw a pebble behind the head of the lead soldier (originally played by The Warden), and his father moved in to protect his son from a retaliatory firebending attack.
The waterbending scroll
- Katara obtained the waterbending scroll, from which Katara and Aang learned the key forms of waterbending.
The Winter Solstice, Part 1
- Aang has the ability to enter the Spirit World, serving as a bridge between mankind and that world.
- Iroh's Siege of Ba Sing Se was mentioned but reduced to 100 days instead of 600.
The Winter Solstice, Part 2
- Sozin's Comet was due to arrive in three years (less than a year in the series). Its arrival will provide the means to achieve the final victory for the Fire Nation's imperialistic war.
- In the novelization, the Fire Nation had caught up with Sokka and Katara (Aang was with them in the series). They were about to be taken out until they were saved by Freedom Fighters grappling down from the trees, the roles taken over by the Kyoshi Warriors in the movie. Sokka tried to help but the fighters took out the Fire Nation soldiers before he had a chance to do anything.
- Ozai banished his son to chase after the Avatar, something he never expected Zuko to succeed with, a fool's errand. With the return of the Avatar, Zuko may actually succeed and return home.
- Ozai burned the scar into Zuko because he refused to fight him in the Agni ki Duel, which was his punishment for speaking out of turn, in opposition of sacrificing novice soldiers in a battle.
- Aang was known to be the Avatar after he choose four items out of many, the same items chosen by a past Avatar.
- Aang ran away because he was to be separated from his family, Monk Gyatso.
The Blue Spirit
- Aang was captured by Zhao and chained him up. Zhao assured he will not kill him as the Avatar will just be reborn again.
- The Blue Spirit snuck into the place Aang was kept, by hanging underneath a vehicle. He used his swords to free Aang, then fought alongside with him against the Fire Nation soldiers.
- The Blue Spirit threatened to kill Aang unless they were both allowed to leave. Zhao had to let them go.
- The Blue Spirit was taken down by an arrow struck to his face, a fatal injury avoided by the mask. Aang discovered it was Zuko and escaped with him.
- Aang camped out and took care of Zuko. In the novelization, he left jumping from tree to tree, with Zuko shooting fires at him, just like the series. In the movie, he left before Zuko woke up.
- Aang suggested to Zuko that they could have been friends.
The Waterbending Master
- Katara was shown training alongside Aang with Master Pakku.
- Zhao attempted to kill Zuko for aiding the Avatar as the Blue Spirit and thought he succeeded.
- While the episode has Zhao discovering the identity of the Blue Spirit (noting that on the wall of Zuko's quarters are the same Dual dao swords that The Blue Spirit), the movie has Zhao rushing to that conclusion despite lack of conclusive evidence (which the character acknowledged in the movie).
The Siege of the North
- The death of Iroh's son in the Siege of Ba Sing Se was mentioned, unnamed but it is likely Lu Ten.
- The Northern Water Tribe knew the Avatar's arrival would bring great danger to them, so they decided to plan ahead their war strategies, and assigned Sokka to be Princess Yue's bodyguard in the process.
- When Yue was a stillborn baby, she was given life by the Moon, her hair turned white since then.
- As the Fire Nation fleet approached the Northern Water Tribe, ashes fell all over the city like black snow flakes, which confused Yue. Sokka recognized the ashes as coming from the engines of the Fire Nation ships, and advised Yue of an imminent invasion.
- The Fire Nation's massive armada attacked the Northern Water Tribe. They were aware of the risk of fighting as the day comes to an end, with waterbending enhanced by the Moon Spirit.
- The Moon and the Ocean Spirit took the mortal form of koi fish, swimming together in a Yin and Yang circle inside the Spirit Oasis.
- Zuko snuck into the Northern Water Tribe by diving into the water and broke into the surface inside the city using his firebending.
- Zuko fought with Katara at the Spirit Oasis and won. He took Aang who still was meditating.
- Zhao discovered the location of the Moon and Ocean spirit from the Great library.
- Aang took part in the Northern Water Tribe battle with the Fire Nation.
- Zhao captured the Moon Spirit into his pouch. When Zhao kills the Moon Spirit in the film, the moon turns red, although in the series the moon turned red when the Moon Spirit was captured, and disappeared altogether when it was killed.
- After Moon Spirit is killed, Iroh acted and moved Zhao and his men out of the scene.
- Iroh noticed Yue has the life of the Moon within her and pleaded her to revive the Moon. In the movie, Yue gave her life back to the Moon so she died. In the series, Yue became the new Moon Spirit.
- Yue gave Sokka her final kiss.
- Zhao was killed after being engulfed by water spiraling under the bridge from the river canal below.
- Aang used the power of the Ocean to the defeat the Fire Nation fleet and drove them away. In the novelization, he took out a few ships just like the series. In the movie, he warned them that he could, giving them a chance to turn around, as a show of mercy.
- The Northern Water Tribe bowed to Aang, although in the series, it was in the presence of Koizilla Aang.
- Back at the Fire Nation, Firelord Ozai gave Azula a task.
Sokka saw smoke behind the trees at a distance, then realized that the Fire Nation was following them.
- The Dragon Spirit suggested that Aang was unable to control his waterbending because of his guilt over the loss of his people and his responsibilities for their deaths. This was improvised from the episode "The Guru", where Guru Pathik told him let go of his guilt to open his water chakra. In the novelization, the Dragon Spirit instead told Aang he may have to choose between his feelings for Katara and being the Avatar, which is in reference of Guru Pathik telling Aang to let go of worldly attachments, i.e. his feelings for Katara, to open the seventh chakra.