US Airways Group Inc.\'s tentative contract agreements with the Transport Workers Union at American Airlines parent, AMR, boosted the labour group\'s leverage in talks with the bankrupt carrier, a banker said. The TWU last week joined unions for the airline\'s pilots and flight attendants in reaching contract terms with Tempe, Arizona-based US Airways. The accords are contingent upon a merger of the two airlines. The US Airways agreement is part of TWU\'s strategy to keep all options open as it battles to protect jobs for its members, said Peter Kaufman, president of Gordian Group LLC. The union remains in talks with American, even as it argues in court today against the airline\'s attempt to reject existing contracts.