British Airways' parent company International Airlines Group says that it has signed a non-discourse agreement with American Airlines, allowing it to look at the company's books.
      Foreign investors are prohibited from owning more than 25 percent of a U.S. airline. The two airlines already have a joint business agreement for flights across the Atlantic Ocean and were founding members of the OneWorld frequent flier alliance.
      Earlier on Friday US Airways and American's parent, AMR Corp., announced that the two airlines had signed similar agreements, moving them one step closer to a potential merger.
      AMR Corp. entered Chapter 11 bankruptcy protection on Nov. 29, 2011. American Airlines CEO Tom Horton has said his airline is weighing several options, including remaining independent or merging with one of several airlines.