Spirit Airlines flight

Airlines boost on-time rating, but Spirit often runs late

Perhaps then it is no surprise that Spirit has the highest complaint rate of any major U.S. airline.

Spirit, a low-fare, high-fees carrier with a clientele of mostly leisure travelers, had by far the worst on-time performance in June among 14 airlines tracked in a government report. Only 49.9 percent of its flights arrived within 15 minutes of schedule, which is the government's definition of being on time.