Delta Air Lines Inc. (search) , which is reorganizing under protection from the federal bankruptcy court, announced plans Friday to discontinue its discount carrier Song and incorporate Song's fleet into Delta's regular service.

Song will continue to fly as a separate brand until May 2006, Delta officials said.

After May, Delta plans to refit the single-class Song airplanes to include first-class seating to make the planes conform with Delta's regular service. The planes will be gradually be repainted in Delta colors by next fall.

Joanne Smith, currently president of Song, has been named vice president of consumer marketing for Delta, effective immediately.

Atlanta-based Delta filed for Chapter 11 bankruptcy protection (search) from creditors in New York on Sept. 14. Song filed for bankruptcy protection the same day.

Delta officials said there will be no layoffs directly from Song's elimination. Any reductions that do occur are part of the 7,000 to 9,000 job cuts Delta announced last month as part of its bankruptcy restructuring, a spokeswoman said.

Delta expects to cut marketing and other costs as a result of closing Song, but the company did not release estimates.

Song was created in 2003 as a hip travel option for leisure travelers, with amenities such as increased leg room, preflight meal ordering and even a music service. It was designed to compete with JetBlue Airways Corp. and other low-cost airlines.

Song has 48 Boeing 757-200 (search) aircraft. It flies from 16 locations, including Boston, Hartford, New York, Seattle, San Francisco, Los Angeles, Las Vegas, Atlanta, five cities in Florida and three Caribbean vacation spots — Nassau, San Juan and Aruba.

Delta did not release figures on Song's profits or losses. But company officials said they considered it a hit with customers: This year Song has filled 78 percent of its seats, Delta officials said.

Song also has been a successful lab experiment that allowed Delta to try new services, said Jim Whitehurst, Delta's chief operating officer.

Delta is adopting new uniforms, new leather interiors, improved in-flight entertainment systems and other Song features. The airline already has picked up on Song's simpler fare system.

"Overall, Song has been a home run," said Paul Matsen, Delta's chief marketing officer.

Despite its success, Delta officials say they wanted the flexibility to use Song's aircraft on other routes. In addition, some Song fliers wanted a first-class option, the airline said.

But aviation industry expert Robert Shumsky, an associate professor of business at Dartmouth College, said Song should be counted as an example of a failed attempt by a hub-and-spoke carrier to create low-cost, non-hub 'airlines within airlines.'

"It's hard for me to believe they would end something that was working well," Shumsky said.