Jet appears to have died during his battle with Long Feng beneath Lake Laogai, particularly since he is never seen or heard from again. The possible death, however, occurs off-screen, and no mention of death or survival is ever made.
The ambiguity of the death is referenced later in The Ember Island Players as the group watches the play.
Zuko: Did Jet just... die?
Sokka: You know, it was really unclear.
The Avatar Wikia claims death, but offers no citation other than the episode which is unclear to begin with.
Is there any canon confirmation or word of god that Jet lived or died after the battle at Lake Laogai?