N. Bruce Ashby, an architect of US Airways Group Inc.'s bankruptcy reorganization and its pending merger with America West Holdings Corp., will resign from the airline by the end of the month.

Ashby, 44, the airline's head of marketing, will become chief executive of IndiGo, a start-up, low-cost airline based in India, US Airways said in a written statement yesterday.

Ashby's departure comes a month after a bankruptcy court judge sharply limited funding for the airline's severance and retention plan for more than 1,800 managers and senior executives. US Airways sought $55 million for the plan and was awarded $15 million.

"It's uncertain as to whether there will be more [executive resignations] and over what period of time," said US Airways spokesman David Castelveter.

US Airways sought the severance and retention funding to keep top executives from fleeing during the bankruptcy reorganization and the preparations for the America West merger.

Ashby was part of the US Airways steering committee that helped orchestrate the merger agreement. US Airways executives said yesterday that the merger was on track for completion by late September or early October. The combined airline, which would operate under the US Airways name, would be based in Tempe, Ariz., America West's home town, and be led primarily by America West's senior executives.

Ashby was also in charge of the airline's frequent flier program.

His departure was not expected to disrupt US Airways' operations or the merger, airline experts said. "US Airways has plenty of capable people to step in," said Darryl C. Jenkins, visiting assistant professor at Embry-Riddle Aeronautical University in Daytona Beach, Fla. "America West is doing most of the heavy lifting here."

IndiGo, which is expected to begin flying by mid-2006, recently announced the order of 100 single-aisle Airbus A320s valued at $6 billion.

One of the lead investors in IndiGo is Rakesh Gangwal, who resigned in late 2001 as chief executive of US Airways. Ashby served under Gangwal as US Airways' vice president of planning.

N. Bruce Ashby plans to step down as US Airways' marketing chief by the end of July to lead IndiGo..