Factual error: In the classroom where Jack argues with Roger next to the chalkboard we can see a poster of the periodic table of the elements. We can see some elements that wouldn't be there in 1977 since they weren't discovered until 1999.
Continuity mistake: When Miles and Hurley deliver The Package, the way it's held is constantly changing.
Continuity mistake: When Miles is sent to deliver "The Package" (i.e. the dead body) to Dr. Chang, after the body is taken out of the van, Miles is seen closing the door to the back of the van. After a return from a flash forward and back to 1977, the door to the back of the van is open again.
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 ★