Says airline funded only 30% of plan; will give $2.1B to 36,000 active and retired ground workers. WASHINGTON (Reuters) - The agency that backs corporate pensions said Friday it was taking over United Airlines' pension plan for ground employees, saying the plan operated by the bankrupt airline was only 30 percent funded. The Pension Benefit Guaranty Corp. said it would guarantee payment of an estimated $2.1 billion in benefits out of the plan's $2.9 billion shortfall. The plan has more than 36,000 active and retired employees, the agency said.