AMR Corp.'s American Airlines, which has agreed to share financial information with suitor US Airways Group Inc., is seeking a one-month extension of a deadline for filing a plan to restructure and exit bankruptcy, Bloomberg News reported yesterday. American, which faces a Dec. 28 deadline to submit the plan in court, asked for an extension to Jan. 28 in a filing today in U.S. Bankruptcy Court in Manhattan. The request is supported by the committee representing unsecured creditors.