Spirit Airlines is known for a lot of things, namely fees and quirky advertising, but one thing it isn’t known for is punctuality or service. According to the Department of Transportation, this past April, the most recent month for which data is available, only 73.4 percent of Spirit’s flights arrived on time—dead last among the airlines that report to the DOT. The average on-time rate for April was 84.5 percent. For 2015, the airline averaged a 69 percent on-time arrival rate. That’s bad.