In Britain, "bender" is a slang term for a male homosexual, so lines in this movie such as "Look out, he's a bender!" resulted in plenty of giggling in UK movie theaters, making it difficult for audiences to take the film seriously.
Noah Ringer submitted an audition tape of himself doing martial arts with a completely shaved head with Aang's signature arrow tattoo painted onto his forehead to Paramount Pictures. This video is what won him the role.
The film was originally titled "Avatar: The Last Airbender (2005)", after the TV show it was based on. However, James Cameron and 20th Century Fox had already registered the film title Avatar (2009), so the word was dropped from the title to avoid confusion.
Dante Basco, the actor who voiced Zuko in the original series, wanted to play Zuko in the film. Many of the producers also wanted Basco to play the role, but M.Night Shymalan had already chosen Dev Patel for the role. Supposedly some people also believed that Basco, who was in his thirties at the time, may have been too old to be portraying a teenager in a live action movie despite this, apparently few people had any objections to Jackson Rathbone being at least ten years older than his character (Sokka) during the time in which filming was taking place.
Tied with The Twilight Saga: Eclipse (2010) for the most Razzie nominations at the 2011 Razzie Awards, the award show honoring the worst motion pictures of the year. Each film had nine nominations. Airbender was nominated for every category besides Worst Actor and Worst Actress. The movie ended up winning five of the Razzies it was nominated for, including Worst Picture of the year. One of those awards was won by actor Jackson Rathbone, who appeared in both films and thus, was awarded the Worst Supporting Actor trophy for that year.
Sokka's stone-tipped spear, the knife in his belt, and a trident harpoon seen briefly in his tent, were all made by Barry Howe of Lethal Lithics in Wisconsin, USA. Not made of plastic or rubber, these are actually very dangerous weapons.
Almost 30 minutes of footage was cut from the theatrical release because Paramount Pictures wanted the film converted to 3D as quickly as possible, in an effort to save money. They had already invested over $150 million into the movie's production.
A scene involving the Kyoshi Warriors and the introduction of their leader Suki (Sokka's other love interest) was filmed but removed from the final cut, due to the director's belief that it was a separate story and would only distract from the movie's main storyline.
According to M. Night Shyamalan, the "mispronunciation" of the names of some of the characters (Aang, Sokka, Avatar, etc) is due to the fact that he wished to 'honor the source material' and use the Asian pronunciation.
Another "giant change" M. Night Shyamalan made from the animated series to the big screen was to limit the Fire Bender's source of fire. Only the highest of the Fire Benders can conjure flames from their chi.
Rather than software, computer graphic cards were the basis for "bending" the elements, allowing previews to be viewed more swiftly. This resulted in M. Night Shyamalan directing more than sixty takes before the effect was finished and lined up with his visions.
The first Nickelodeon movie based on a Nicktoon to ever be nominated for a Razzie award, no others have been nominated possibly due to them being animated and it's rare for animated films to be nominated for Razzies.
After the moderate critical success from After Earth, Nickelodeon stated in 2015 that they want M. Night Shyamalan to make a sequel to this film. Shymalan has confirmed that he will be working on the sequel after his next "thriller".