The Langoliers is one of four novellas published in Four Past Midnight (1990) by American horror novelist Stephen King.

The Langoliers are fictional boogeymen of sorts from Craig Toomey (Bronson Pinchot)'s imagination. Toomey's father described them as having big teeth and eating kids who are lazy and don't get with the program. Toomey's description of the Langoliers so closely resemble the Timekeepers of Eternity, as passenger Bob Jenkins (Dean Stockwell) calls them, that the passengers take to calling them that.

Remember that this is fiction a la Stephen King. In King's story, the Langoliers eat the Past in order to keep time balanced and stable and to make room for the Future. Here's an example. Say that you have a computer with a 20 gigabyte harddrive on which the Past, the Present, and the Future each take up 10 gigabytes (which makes 30 gigabytes). You've opened a tremendous video file that takes up the whole 10 gigabytes allotted for the Present. After watching this video, it is transferred to the Past because it's been used and provides no more use to you. Now you go on to the next video, and you also have another video you want to download, but your harddrive is now full. The old video takes up the Past 10 gigs and the video currently in play takes up the Present 10 gigs, so you can't download the new video until you make space. The video you're watching is in use in the Present, so you don't want to delete it to make space for the new video. However, the video you just watched is over. It has served its purpose. It's in the Past. It's time to make room for the new and, thus, it is deleted so that you can download your next video. This is the function of the timekeepers aka the Langoliers. They constantly clean up an empty and useless physical spectrum of a world that can no longer be of use to anyone. They keep the time spectrum clean and continuous and make room for the Future.

That question is not answered, either in the movie or in the novella. Explanations offered by viewers include (1) experiencing the beauty of the rip was simply too much for the mind, (2) a person must be doing exactly what they were doing when they first crossed the rip, and (3) it keeps the Langoliers from entering the present because they never sleep. Stephen King also used this specific plot device before in "The Jaunt", a 1981 short story. In "The Jaunt", people could travel incredible distances through portals, but they had to be asleep (or knocked out) to survive the trip or they would suffer severe damage to themselves, physically as well as mentally.

Another question that is not answered in either the movie or the novella. There are two possible explanations: (1) They ceased to exist/died. (2) Their bodies stayed in the present, while the plane, their metal belongings and sleeping passengers traveled to the past, which means they plummeted to their deaths.

Dentures, watches, rings, surgical pins, and wigs of the awake passengers were left behind. The common denominator seems to be that objects containing metal cannot pass through the rip. As for the wigs, there may have been bobby pins, clips, or something metal in the weave.

The pilots had set the flight on autopilot.

When Brian and Nick were discussing their "secrets", Brian mentions that he and his wife got divorced and it ended badly. The thing he did that he never thought he would do was to hit his ex-wife. In the novella, Brian reflects on this moment where they were fighting about having children and his wife insulted him. In a flash of anger he slapped her across the mouth, something he was disgusted with himself for doing and immediately regretted it.