Ailing airline may end all of its pension plans, creating the biggest default in US history and forcing a possible bailout. NEW YORK – Despite ongoing negotiations with its unions, United Airlines has told the bankruptcy court that the "likely result" will be a decision to terminate all of its pension plans. That would precipitate the biggest pension default in history, more twice the size of the Bethlehem Steel Corporation default in 2002. The move is expected to destabilize the already struggling airline industry, prompting other old-line carriers like Delta to eventually follow suit to maintain competitiveness. It would also...