US Airways said Wednesday it has grounded its $9.8-billion US takeover bid for rival Delta Air, which is forging ahead with its own plans to reorganize under bankruptcy protection.

US Airways said it was told earlier in the day that Delta's official unsecured creditors' committee would not meet several demands from it by a Feb. 1  deadline.

"We are disappointed that the committee, which has been chosen to act on behalf of all Delta creditors, is ignoring its fiduciary obligation to those creditors," said Doug Parker, the chairman and CEO of Tempe, Ariz.-based US Airways.

"Our proposal would have provided substantially more value to Delta's unsecured creditors than the Delta stand-alone plan," he said in a release.

In mid-December, after US Airways made an initial takeover play, Atlanta-based Delta rolled out a five-year business plan which envisions the company getting out of bankruptcy protection this spring.

Delta has been in bankruptcy protection since September 2005.