(at around 1h 19 mins) Laurel claims that Los Angeles is deserted, yet cars can be seen moving.
The entire time Laurel is watching Mr. Toomy being chased and devoured by the Langoliers, the moving staircase is visible. It can even be seen as the plane begins to move and Nick pulls Laurel out of the doorway and closes the cabin door, but in spite of its location toward the front of the plane obstructing the starboard wing, it seemingly "vanishes" as the plane leaves.
(at around 49 mins) When the plane leaves Bangor, the captain raises the landing gear. In a subsequent shot, they are down again.
(at around 1h 20 mins) When the survivor landed LAX, Brian is wearing headset. At the next shot, he is not wearing it. Finally before crashing the plane, he is wearing the headset again without putting it back.
(at around 1h 20 mins) Right before landed into LAX, we see Albert sit in the right side of the plane. But when the plane turning, we see Albert in the left side of the plane.
(at around 1h 20 mins) Attempting to steer an airplane moving along the ground at more than 100 knots will cause the landing gear to be destroyed.
(at around 1h 4 mins) When the plane is flying towards LAX, the flight computer graphic has the plane flying towards Bangor.
(at around 1h 20 mins) During his landing at LAX, the pilot repeatedly veers the aircraft using the yoke. However, aircraft are not controlled on the ground using the yoke, but by the small hand tiller he is seen using while taxiing at Bangor.
(at around 51 mins) On takeoff, while the plane is lifting off the ground, the shows that the aircraft is pointing down and lifting to straight flight.
(at around 49 mins) When the plane takes off in a steep climb to escape the creatures, the scene in the cockpit reflects a steep climb, while scenes in the passenger cabin shows a dive or descent.
When the survivors are waiting in LAX for time to catch up, there is a shot where you they are standing in front of the windows of the terminal. People can clearly be seen walking around in the next terminal through the windows behind them.
(at around 20 mins) After Craig Toomey is hit for the third time by Albert and his toaster weapon you can see the reflection of a baggage car drive by in the window, even though the ten people are supposed to be the only people there.
(at around 40 mins) As Brian is about to climb up the steps to uncouple the fuel pipes (with Nick following behind), on the left side of the picture (just over Brian's shoulder), a shadow can be clearly seen moving under the gantry to the terminal.
(at around 44 mins) Before the plane takes off from Bangor airport to escape the Langoliers, it is parked with stairs connected to its front left escape hatch. When it starts to move forwards towards the runway, the left wing should crash into the stairs.
(at around 1h 2 mins) On the return flight to LAX one shot of the flight path not only shows the plane heading towards DAG but also shows LAX as LAS.
Supposedly, chemical reactions don't happen outside the plane in the world of the past (matches don't light, food and drinks are totally tasteless, e.g.). Dakin, Kymberly's character Doris is able to light a cigarette outside of the plane.
The U.S. Bank Tower is missing from the Los Angeles skyline. The film is set in 1995, and the building was built in 1989.
When Nick asks Brian "what now" after attaching the fuel hoses Brian responds, "I'm gonna use the engines to suck the gas out of the fuel pads". The L-1011 uses Jet Fuel not Gasoline. An experienced airline captain should know better.