Craig Toomy: Oh I'm real scared now.
Nick Hopewell: Do you ever watch Mr. Spock on Star Trek?
Craig Toomy: What the hell are you talking about?
Nick Hopewell: Because if you don't shut your cakehole, you bloody idiot, I'll be happy to demonstrate his Vulcan sleeper-hold for you.
Answer: No, they didn't die. The premise of the story is that the sleeping plane passengers were in an alternate timeline a few minutes out-of-sync with normal time; so, when they awoke, they were aware of a dead zone in the immediate past. Everyone else in the world is still alive in the present. The "Langoliers" were interdimensional creatures that fed on the past, gobbling it up like a stage-cleaning crew.
Charles Austin Miller