Creditors said that American Airlines would have to start over in its effort to restructure in bankruptcy after two years if the U.S. succeeds in blocking the carrier’s planned merger with US Airways Group Inc., Bloomberg News reported yesterday. The bankruptcy would go back “to square one with likely disruption and disarray among numerous, financially unaligned stakeholders,” the committee representing American’s unsecured creditors said in a court filing yesterday. American parent AMR Corp., which filed for bankruptcy on Nov. 29, 2011, was set to exit court protection by merging with Tempe, Arizona-based US Airways when the U.S. Justice Department and a group of states sued the carriers in August. The government says the merger would reduce competition while the airlines defend the deal as benefiting consumers. The trial is set to begin Nov. 25 in Washington, D.C.