Baggage fees up 33 percent in the first quarter

During the first quarter, airlines also charged $554 million for reservation change fees, with Delta receiving the most revenue at $165.3 million, a 90.2 percent increase over last year. 

Total first quarter airline revenue from all ancillary sources was $1.86 billion, 6.2 percent of all revenues for the 28 airlines responding. 

Delta led the way overall at $592 million, a 61.2 percent increase over the same period last year. American Airlines, which lost money in the first quarter, collected $261 million, or 8.2 percent more than 2009. 

Spirit Airlines, which reported $40 million in revenue, reported the largest percentage — 21.7 — of operating revenue from ancillary revenue of any carrier.

Airlines also reported revenue of $534 million from other revenue such as frequent flyer program mileage sales and pet transportation fees.

In operating profits, Delta led the way with a $107 million, while American showed a $322 million loss. 

Meanwhile, the seven low-cost carriers, including Southwest, Allegiant Air, Spirit and Comair, reported a 2.4 percent profit margin with profits of $115 million.  

Southwest reported the highest profit at $54 million but Allegiant's profit margin was the highest at 20 percent. 

Virgin America, reported the largest loss for a low-cost carrier at $19 million. 

The six reporting regional carriers posted a $60 million, or 3.9 percent, profit margin.