American Airlines parent AMR Corp. is seeking a three-month extension to its exclusive right to file bankruptcy reorganization plan as a pilots union vote pushes back the timetable for winning labor savings, Bloomberg News reported on Friday. Extending the deadline to Dec. 27 from Sept. 28 would delay any formal merger proposal to creditors from US Airways Group Inc., which is weighing a takeover. It also may mean missing American Airlines CEO Tom Horton’s goal of a 2012 bankruptcy exit as he works to keep Fort Worth, Texas-based American independent while the airline restructures. While pilots union leaders agreed last week to let members vote on $315 million in givebacks, balloting will not end until Aug. 8.