Aang (pilot)

In the pilot episode, Aang was very similar to himself in the first book of the main series. He was fun-loving, somewhat naive, and adventurous. He also seemed to already have a conscience against killing people, as he saved Zuko from, at the very least, a critical injury towards the end. He already had had some waterbending experience, as he bent the water and both corrected Kya's attempts and gave her advice.

Notably, the Avatar State was much more simplistic in the pilot; Aang threw himself into danger to activate it, and seemed to be able to come out of it at will as well, seemingly indicating mastery. Obviously, the concept of the Avatar State was much more complex in the show, as the current Avatar reincarnation is not born with mastery of the state, and it activates only when it is in real danger or from extreme emotion; also, Aang didn't master it until the very end of the series.

History
Aang, Kya, and Sokka were together fleeing Prince Zuko on his ship. They ran into a sea serpent, but it took interest in Zuko's ship rather than them, and allowed them to escape to an island. When there, Kya practiced her Waterbending, but could not control it well; Aang offered her some advice and demonstrated the correct leg stance. When Sokka demanded them to help search for food, Kya was reluctant to leave Aang, "the world's last hope", and so Sokka went off in a huff. Kya and Aang waited around, and engaged in a slightly awkward conversation before Momo alerted them to danger.

When they reached the Fire Nation base and saw Sokka being taken in, Kya decided to go after him but told Aang to stay hidden. She got captured as well, but refused to reveal Aang's wherabouts. When Aang flew in, shocking everyone, the soldiers threw Sokka and her into a pit. Aang sat on the scaffolding evading Zuko's attacked while Momo distracted the soldiers and then engaged Zuko's pet hawk in a flying duel of sorts.

As the scaffolding disintegrated, Aang and Zuko moved their fight to the defaced Avatar statue. When Aang was almost cornered by Zuko, he simply threw himself off the statue, activating the Avatar State and blowing Zuko off. Coming out of the Avatar state, Aang caught an unconscious Zuko, but dropped him a short distance into a wall to fly over to Kya and Sokka and subsequently escape.

Similarities to Real Series

 * Aang already seemed to have feelings for Kya, as noted by Sokka's "boyfriend" comment, recreated in the actual series in "The Avatar Returns" and "The Fortuneteller".
 * He saved Zuko from falling to his certain death; he similarly saved Zuko from a near certain death in "The Blue Spirit" and" The Siege of the North Part 2".