On Sept. 12, 2001, there were no commercial flights in the United States. It was uncertain when airlines would be permitted to start flying again—or how many customers would be on them. Airlines faced not only the tragedy of 9/11 but the fact that economy was entering a recession. So almost immediately, all the U.S. airlines, save one, did what so many U.S. corporations are particularly skilled at doing: they began announcing tens of thousands of layoffs. Today the one airline that didn't cut staff, Southwest, still has never had an involuntary layoff in its almost 40-year history. It's now...
