In the movie The Net a flight appears as "hijacked" on a departure/arrival screen. Would these screens really show an airliner as hijacked when they are, and did this ever happen?
I don't have any experience with the software used (at LAX or anywhere else) but here are my thoughts.
In theory anything can be shown if the display is connected to a general-purpose computer, but I doubt the software displaying flights and times has "hijacked" as a selectable status, or that it has a free-text entry option.
The hack would, in all likelihood, have to be an edit to the compiled binary/executable of the program that is shown on the screen, similar to the story about the "Thank you for playing Wing Commander" error message. This could change all instances of "Delayed" to show "Hijacked" instead (though there are more letters in "Hijacked" so this may not even be possible). The string "Delayed" could also be stored outside the binary in a manner similar to the
.strings system Apple uses, which would make editing it easier. But in both cases the change would be seen for all delayed flights rather than just one.
Or it might be that the flight information is stored in a database separately before being passed to the binary which displays it on the screen; if "flight status" is stored as a plaintext string instead of a numeric code (to be decoded within the binary) it would be very possible to change the status for one flight in particular to be anything you want. Personally I doubt this is the case because the system needs to get information automatically from some central location and is continually updated by feeds from the airlines. But the hackers may have disabled automatic updates as well.