Complaints against airlines rise, Spirit second worst

Airlines are getting slightly better at staying on schedule, but that isn't keeping complaints from rising. More complaints were filed from consumers in March than in the previous month or March of 2014, the U.S. Department of Transportation said Monday. Miramar-based Spirit Airlines (Nasdaq: SAVE) had the second-worst rate among all carriers. Another discount carrier, Frontier Airlines topped the list with passengers 34 times more likely to complain than consumers on Southwest Airlines, which…