The chief executive of US Airways dismissed as "unrealistic" on Thursday a plan by Delta Air Lines to emerge from bankruptcy as a stand-alone company worth up to USD$12 billion.

Speaking on a conference call with reporters and analysts, Doug Parker said Delta's management also exaggerated the potential antitrust issues that could delay or prevent government approval of US Airways' proposed merger.

Delta on Tuesday formally rejected US Airways' takeover bid, which currently amounts to USD$8.3 billion, and filed a plan to emerge from Chapter 11 as an independent company. Delta assigns a value between USD$9.4 billion and USD$12 billion to the carrier.

"We think their valuation is way out of whack," Parker said, explaining that Delta used a valuation method that differs from US Airways' method.

"Their methodology is extremely aggressive and lacks credibility. Our proposal is superior on any methodology."

In a statement later on Thursday, Delta said its stand-alone plan would provide creditors with better value, a faster recovery and much greater certainty of execution.

"Nothing we heard today explains away the fact that the US Airways proposal provides inferior value to our stand-alone plan," the airline said.

US Airways' plan "is structurally flawed, and raises overwhelming regulatory and labor issues that -- after a lengthy delay -- are likely to prevent the proposed merger from being completed."

Delta, which has been in Chapter 11 since September 2005, has said repeatedly it plans to exit bankruptcy as a stand-alone company, despite the takeover proposal that US Airways says could produce USD$1.65 billion a year in savings for a combined carrier.

US Airways, however, has said it remains a bidder for Delta and hopes that the carrier's creditors committee will persuade management to reconsider. At this stage, US Airways is seeking permission to examine Delta's books.

Parker said Delta has overstated the challenges of combining the labor forces of the two airlines. He also said any antitrust concerns would be manageable because the two carriers have very few nonstop routes that overlap.

"We have done a tremendous amount of work on this," Parker said. "These antitrust issues are fully manageable."

Delta said its five-year business plan filed with a US bankruptcy court on Tuesday would result in a recovery for Delta's unsecured creditors of about 63 percent to 80 percent of their allowed claims. It assumes a total claim pool of about USD$15 billion.

Creditors holding at least two-thirds of the value of total impaired claims -- debt that will not be repaid in full -- must vote in the plan's favor for it to succeed. The bankruptcy court also needs to approve the plan.