Spirit Airlines filed for bankruptcy protection, the first big carrier in America to go bust since American Airlines in 2011. Spirit, a low-cost airline, has not made an annual profit since 2019 and, like other discount rivals, has seen ticket prices plunge amid a surplus of seats. In January a judge blocked its takeover by JetBlue Airways on competition grounds. A mooted merger with Frontier Airlines also came to naught. Spirit regularly features at the top of lists of America’s most hated airline, a crowded field.