The show changed production designers after the pilot episode was filmed, resulting in a different appearance for CTU HQ in from the second hour onwards.
In the first episode a commercial airplane gets blown up and hundreds of people die yet the whole thing gets dropped from the plot starting the next episode as if the whole thing never happened. No one ever mentions the incident in any of the future episodes, not even news reporters and life goes on in LA as if nothing happened.
When Jack calls Vincent, the time on Vincent's clock reads 12:06, despite seven minutes having passed in the episode.
The 747 that explodes over the Mojave Desert is stated to have flown direct from Berlin, where the assassin is supposed to have been hired. Berlin doesn't have an international airport, and won't until the new Berlin-Brandenburg International Airport is completed around 2010. The Schoenfeld, Tegel and Tempelhof airports that currently serve Berlin cannot accommodate a 747, and any flight from Berlin to the U.S. would have to connect from Frankfurt or Munich.
At the very end as the girl gets sucked out the plane and the plane blows up, as she is parachuting down you can see daylight on the horizon. Not physically possible in California if its 12:59am.
When Mandy blows the airplane hatch open, the vacuum created causes her to be sucked out instantly, yet the - much lighter - debris seems to move in all directions (some of it away from the hatch).
The very last shot of Mandy's parachute opening looks like it was shot with an anamorphic lens and not properly desqueezed for the series' 1.85:1 aspect ratio. In the beginning of the following episode, however, the same shot looks correct at the beginning of the following episode.
In the beginning of this episode, Jack is stopped next to a bus on his way to the office. When he drives away, the camera's reflection can be seen in the side of his car.
(at around 36 mins) A small piece of camera moves into the shot on the left.
When David Palmer (The Senator) walks out onto the balcony where his wife and security agents are, it's possible to briefly see a camera on the left hand side of the screen.
When Teri gets up from the kitchen table, the camera pans over too far and a lighting flag can be seen attached to the table on the left.
When Mandy is taking her suitcase out of the compartment, the passenger in the front on the right is holding a large TV camera, pointing it at her,
When Jack knocks Mason out with the tranquilizer dart, he falls and Jack catches him, checking his pulse. However, Jack checks Mason's pulse with his thumb which isn't the correct way as the thumb has its own pulse.