Southwest Airlines’ fourth quarter 2014 total operating revenues increased 4.5% to US$4.6bn, while operating unit revenues increased 2.0%, on a 2.4% increase in available seat miles, all as compared with fourth quarter 2013. The growth in operating revenues was largely driven by strong fourth quarter 2014 passenger revenues. Operating income in fourth quarter 2014 was US$621m, compared with US$386m in fourth quarter 2013, resulting in a 13.4% operating margin. Excluding special items, operating income was US$679m in fourth quarter 2014, compared with US$418m in fourth quarter 2013, a 62.4% increase year-over-year. For 2014, total operating revenues increased 5.1% to US$18.6bn, and total operating expenses were US$16.4bn, resulting in operating income of US$2.2bn, compared with US$1.3bn in operating income for 2013.