This doesn't feel like an organized 'sick out', but rather more like a frustrated population of employees who know the end is near. A couple of good points already pointed out in this thread back this up, i.e., no objective, and no positive effect on public perception.
My philosophy: Generally, people will do what is in their own best interests. Given the current situation, the perceived imminent demise of USAirways, the employees recognized that a day's worth of sick pay, plus the ability to be home on Christmas, was worth more to their own self interests than coming to work that day.
Where USAir management failed in this situation was in the perceptions that have obviously been fostered amongst their employees. If the employee population feels that they are better served by not coming to work, regardless of the consequences, then management has failed. With no employee support, the objectives of the organization, any organization, can not be accomplished.
Treatise on employee relations: Make people want to come to work.
(The worst way to do this is to try to motivate people with money. Bad for the bottom line on the statement of income, bad for the morale of the people who work for that company.)
Motivate people by making the objective of the organization the objective of the people. If the people meet their objective, the organization meets its objective.
Leadership. You don't need a corner office with a wall of windows to be a leader. You don't need to drive a shiny Mercedes to be a leader. Your don't need to have a great golf game to be a leader.
To be an excellent manager, you need to be a great leader. The CEO of a successful airline should be a pilot. He or She should fly a regular line flight at least once a month. Also, that person should work a late shift as a gate agent at least once a month. IF this person requires an office, that office should be the smallest cubicle in the building that is the farthest from any window. That person's reserved parking space should be the farthest from the building.
These are all signs of a great leader.