Remember when the building in Oklahoma City was blown up. Within hours we had pictures or drawings of possible suspects plastered all over the media. Why not the same for Flight 23, an obvious terriorist hijacking attempt?
Possibly because the authorities were tailing them and didn't want to tip them off. If you want someone to lead you to his associates the last thing you need is a "Wanted" poster.
I think it is clear, for good or bad, that the govt. did not want to scare the public further with stories about more terrorists out there free to attack again. These stories disappeared quickly, and that’s about when the tradition began of pronouncing every unusual event as NOT a terrorist attack.