Back in January, Southwest projected that its adjusted nonfuel unit costs would increase by 3% to 3.5% in 2019, with most of the cost creep occurring in the first half of the year. Unfortunately, the grounding of the Boeing (NYSE: BA) 737 MAX in March upended Southwest's plans for the year. With a substantial proportion of its fleet out of service, the carrier has been forced to slash its schedule dramatically, exacerbating its unit cost inflation.