Are Workers Obligated to Drop Everything for 'Emergencies'?

Starting today, the Federal Aviation Administration is requiring airlines to reduce flights at 40 airports because of the strain that air traffic controllers are under during what's turned into the longest federal government shutdown ever. Fewer flights mean reduced supply, just as demand is about to ramp up for the holidays. And there’s gonna be consequences for both airlines and consumers — including likely price increases. Plus, what constitutes a "workplace emergency" these days?