A group representing retired pilots is having second thoughts about its decision not to oppose Delta Air Lines' plans to terminate their pension plan. The group, DP3, asked the federal bankruptcy court to delay a Sept. 1 hearing on Delta's request to terminate the pension plan. The group argued that it needs more time to study pension relief legislation signed into law last week that could open a way for Delta to save the pilots' pensions. Delta wants to shed the deeply underfunded pension plan effective Sept. 2, shifting responsibility for further benefit payouts to a quasi-federal agency. DP3's motion to oppose the termination came late last week, only days before a hearing set for today on the group's earlier pact with Delta. That agreement would have ended the retired pilots' opposition to dumping their pension plan on the Pension Benefit Guaranty Corp.