Don't all those televisions in airports usually show CNN? I think that the people running the Detroit Metro Airport probably changed the channel when the story broke so that the passengers wouldn't get unnecessarily anxious and distracted.
Here were my flight plans on 2009-12-25:
LAS 07:15 -> DTW 14:16 Northwest Flight 2399
DTW 15:50 -> CMI 16:54 Northwest Flight 3224