From Southwest to Spirit, budget airlines are in a tailspin

Today Southwest is America’s biggest domestic carrier and the world’s fourth-largest airline. It turned an annual profit every year from 1973 to 2019, before the covid-19 pandemic struck, with a net margin often exceeding 20%—a striking feat in an industry known for its abysmal returns. Its success has been imitated across the globe. In 2001 budget carriers accounted for less than a tenth of global flight capacity. That figure is now a third, according to OAG, a consultancy.