American Airlines parent AMR Corp., now reorganizing in bankruptcy, expects to reach a decision within weeks on whether to merge with US Airways Group Inc. or remain independent, Chief Executive Officer Tom Horton said.

The company’s board and unsecured creditors committee asked unions at American and at US Airways to help evaluate the benefits, costs and risks of a deal, Horton said Thursday in a memo to employees.

“I can assure you we are conducting a collaborative, fact- based analysis to determine the best path forward for American,” Horton wrote. “While I cannot give you a precise date, I can tell you that we expect to bring this to conclusion within a matter of weeks.”

AMR has a board meeting set for Jan. 9 at which it hoped to be ready to decide whether to go ahead on a tie-up, Bloomberg said, citing unnamed sources. US Airways has been pursuing a merger with American, which filed for bankruptcy in November 2011, to form the world’s largest carrier.