Consumer complaints against airlines are rising even as the carriers get slightly better at staying on schedule.
The U.S. Department of Transportation said Monday that it received more complaints from consumers in March than it did in either the previous month or March of 2014.
While the numbers are still very small — only about one in every 50,000 passengers complains to the government — they vary greatly among carriers.
Passengers on Frontier Airlines were 34 times more likely to complain than passengers on Southwest Airlines, which has the lowest complaint rate. Spirit Airlines had the second-worst rate.
Frontier and Spirit are so-called ultra-low-cost carriers that charge low base fares but add fees for many things including carry-on bags and seat assignments.
A Frontier spokesman, Jim Faulkner, said customers who called the reservations center in March were sometimes put on hold for up to 45 minutes as the airline switched to a new reservations system.
Faulkner said that Frontier added staffing, and hold times have been reduced to under three minutes. He said complaints were down so far in May.
Transportation Department officials recently discussed the complaint levels with both Frontier and Spirit, according to a department spokeswoman. There are no penalties for having a high complaint rate, but the department considers them when deciding whether to investigate potential violations of rules dealing with fare advertising, overselling flights and other consumer issues.
Overall, the March complaint rate among the 14 airlines covered in the government report jumped 27 percent from February and 55 percent from the previous March.
The Transportation Department said that 78.7 percent of flights operated by those 14 airlines arrived on time in March, up from 72.8 percent in February and 77.6 percent in March 2014. The government defines an on-time flight as one that arrives within 14 minutes of schedule.
Hawaiian Airlines — blessed by usually good weather and lots of short flights in its home state — ranked best, while Frontier was last. Frontier said it is increasingly focused on getting the first flight of the morning out on time so that delays don’t cascade throughout the day.
Envoy Air, a regional carrier that operates many American Eagle flights, had by far the highest rates for canceled flights and lost or damaged bags.
Envoy spokeswoman Martha Thomas said that when bad weather hits, American often gives priority to its flights and cancels regional flights with smaller planes and fewer passengers. She said increased staffing and schedule changes at hub airports in Chicago and Dallas have led to better on-time performance in April and May.