What broke Southwest Airlines?

At one point last week, 84% of Southwest Airlines flights through Philadelphia were canceled, and nationally, they were canceling two to three thousand flights a day - right in the middle of the holidays. The airline is back to normal operation now, but what happened? What pushed Southwest to this breaking point, and what can they and other airlines learn from this? Dr. Benjamin Altschuler, Associate Professor of Travel and Tourism at Temple University, helps us explain this travel fiasco.