American airlines dropping like flies

US-based Frontier Airlines is filing for bankruptcy. It's the fourth U.S. airline to file for Chapter 11 in recent weeks, along with ATA, Skybus and Aloha. But unlike the others, it plans to continue passenger service while it reorganizes.

Earlier this week, it was named among the top 5 carriers in the Airline Quality Ratings, a study co-authored by a Wichita State University Professor.

Like all airlines, Frontier is feeling the effects of sky-high fuel prices and turmoil in the financial markets. But the Denver-based carrier blames the bankruptcy decision on an unexpected move by its main credit-card processor to start withholding significant proceeds from ticket sales. Frontier's CEO says the Chapter 11 filing will prevent the processor from increasing its "holdback."

Frontier announced last month that it was coping with higher fuel costs by selling four of its planes.