CHARLOTTE ( TheStreet) -- The Teamsters Union sees an expansion opportunity in the merger between US Airways ( LCC) and American ( AAMRQ.PK), where mechanics work under contracts that were signed during bankruptcies. The Teamsters, who are not part of the AFL-CIO, which prohibits members from raiding other members, said they have filed enough signatures with the National Mediation Board to prompt a union election among the US Airways mechanics, who are represented by the International Association of Machinists. At a press conference in Charlotte, the Teamsters also said they plan to file at American, where mechanics are represented by the Transport Workers Union. Both incumbent unions launched assaults on the Teamsters. The IAM, known for its successful efforts to protect a defined benefit pension plan at United ( UAL) and US Airways, where other workers lack such plans, said Teamster representation would eliminate pensions for US Airways mechanics, who would then have to accumulate retirement assets in 401K plans. The TWU attacked the Teamsters' integrity. "The IBT is behaving like a parasite," said Garry Drummond, TWU air transport division director, in a prepared statement. "They have no agenda except to steal workers from other unions." TWU also said the Teamsters have forged signatures on cards in their campaign to organize American mechanics. In Charlotte, Jim Blanton, a Charlotte-based US Airways mechanic, said Teamsters have collected 2,800 signatures from about 4,500 US Airways mechanics. Of those, 3,505 are active, according to the carrier's fact sheet. "We've seen our level of representation diminish," Blanton said. "Over the last 12 years, the IAM has done a poor job of representing our group." He said an election could take place in two to three months. Eight Teamster backers, most from US Airways, spoke at the event. Some said they had sought out the Teamsters. "We approached the Teamsters because we wanted strong representation on the job," said Ted Vallandingham, an inspector at US Airways in Pittsburgh. "I'm most fed up with the handling of grievances." Bill Wheeler, an American Airlines mechanic in Tulsa, said the union will also file shortly to represent American workers. The Teamsters currently represent 18,000 mechanics and related workers, principally at United ( UAL), UPS ( UPS) and ExpressJet.