Frontier Airlines lowered its rate of complaints considerably in April, and did a bit better than average among major airlines for flying on time for the month, according a monthly federal report today.

The Denver-based carrier in April posted a rate of consumer complaints to the U.S. Department of Transportation of 2.42 per 100,000 "enplanements," or boarding passengers, according the DOT's latest Air Travel Consumer Report.

That's a big improvement over Frontier's complaint rates of 3.39 per 100,000 in March and 4.5 per 100,000 in the first quarter of the year.

Frontier -- the third-busiest carrier at Denver International Airport by passenger counts -- has been plagued by high complaint rates and frequently tardy flights in recent years as it has transitioned into a "ultra low cost" airline and has been struggling to improve performance.

Read more at Denver Business Journal.