NEW YORK (CNN/Money) - Delta Air Lines announced Friday that it plans to merge its discount airline, Song, into its regular Delta service.

Song, launched in April 2003, will continue to fly as a separate brand until May 2006, and customers will be able to book flights until then. After that, it will become part of Delta.

As part of the restructuring, Delta hopes to merge Song's customer-service features with Delta's potentially more profitable routes.

During the next two years, Delta will adopt many of Song's features into existing Delta lines, including improved amenities, such as leather seats, 24 channels of live television, 10 on-demand video channels, video games and a digital-music library.

"We are incorporating the best of Song into the best of Delta," said Gerald Grinstein, Delta's chief executive officer.

Delta, the nation's No. 3 airline, currently is operating under bankruptcy protection.

Delta launched Song to compete with other low-fare carriers, including JetBlue and Southwest. But it did not have as low a cost structure as those carriers.

Delta (Research) has not broken out results for Song, but the company has not been profitable since 2000.

Though rising jet fuel prices have hurt Delta, that has not been the only problem. Some analysts have said that Delta waited longer than some of its rivals to trim costs. It did not win cost concessions from its pilots union until last October, after paying them the highest wages in the industry under a contract reached months before the Sept. 11 attacks.

In addition to Delta, carriers operating in bankruptcy are United, the No. 2 airline, and Northwest (No. 4).

Correction: An earlier version of this story said that US Airways was operating under bankruptcy protection; the company had been in bankruptcy but emerged in September.