General Motors Co has developed contingency plans in case recalls of potentially lethal Takata-made air bag inflators widens, forcing the U.S. automaker to repair millions of vehicles, the company said on Friday. More than 21 million vehicles have been recalled globally by numerous automakers since 2008 because of defective Takata Corp inflators that could rupture and shoot metal shards into the vehicle and have been linked to at least five deaths.