IT WAS HEAVEN

Hold on to your seat belt and oxygen masks.

All the passengers and crew of Flight 815 died in the plane crash.

But that is alright.

Because everything we saw thereafter was the main characters' version of heaven.

The adventure, the romance, the fights, and more importantly, a way that they each wanted to end their own lives - - - on their own terms, in their own way.

When the TPTB weasel their explanation that the ending was about the big life and death question, but don't answer it, then we must our own profound conclusions.

Even poor Locke, in the bitter end in a seedy hotel room, distraught that he could not accomplish his mission, took his own life (abet, at the hands of crazy Ben) which caused the other O6 members to rethink their views on Locke's words . . .  allowing them to return to the island to save their friends. Locke was told he had to die in order to save the island (and his friends). To die to save something more important than one's self is a heroic gesture. Locke's measly life had no heroic elements. If this was his "second chance" at death, then he went out nearly on his own terms - - - a personal sacrifice to help those trapped on the island.

The same is true with Jack. He really did not have to die in the bamboo grove. But that is how he saw himself being the hero, the way "to fix" the island trap that snared his fellow survivors. This is the way Jack saw himself - - - dying as a leader to save his followers. Something his father told him he did not have the stomach to do in real life.

As goofy as the scene played out, Jin wanted to die with Sun in the sinking submarine. He realized dispute all their troubles, he could not live without her. He would sacrifice himself to stay with her so they could be together, forever, in the after life. And in some respects, Sun wanted the same thing. She left her child to go back to the island to find Jin, not knowing if he was alive or dead.

The main characters used some supernatural time space displacement between this world and the next, to change fate and tragedy into their own means of living their mortal coil - - -  finding a little personal happiness in the midst of disaster (which for most, included their off-island, preflight lives.)

There is not to say there are multiple worlds within a single perceived world. Many astrophysics theorists believe that there are multiple universes slightly out of phase with our current visual one. Some theorists also believe in a causal multiverse, where every person's decision opens a new tangential universe time line.

The plane crash event could have split the main characters human time line into several tangential realities: a spiritual universe and a dream universe. In the end, the universes intersect to form a new, third reality.