Other mistake: The Monster appearing in the pilot and causing the turbine to explode is a mistake (not trivia). This is actually an artefact of poor CGI effects that was left in the show in error. It was confirmed by the producers. You can see it best here: http://www.lostpedia.com/wiki/Image:Turbine_Explosion.gif.
Continuity mistake: When Jack drops to his knees, after removing the undershirt, one white shirt lies stretched out horizontally on the ground directly in front of him, with both knees centered in front of it; the other shirt is off to his right (viewer's left), with the undershirt he drops. Three shots later, still on his knees, all three shirts lie rumpled to his right; eleven shots later, the single white shirt once again lies horizontally directly in front of him, in the very same position as the earlier shot.
Chosen answer: None of the main characters died in the plane crash. Many died on the island after the crash (Jack, Charlie, Sun, Jin, Daniel, Juliet, others), some lived on the island for an apparently long time after the crash (Hurley, Ben, Bernard, Rose) but some lived lives off the island after the crash (Sawyer, Kate, Claire, Miles, Aplert, and Lapidus). Remember that Christian tells Jack that "time has no meaning here," (in Purgatory). When everyone meets at the church, they are at the end of their lives however long that may have been and will now "move on" together. They look like they did on the island because that is the way they best remember each other.
Guy
That has to be the clearest explanation of the ending I've ever read.
Ssiscool ★