Eastern Airlines eliminated 2,600 more jobs in the “downsizing” it says it needs to survive, despite a union-led legal challenge to its sweeping cost-cutting program. Eastern previously said it would eliminate 4,000 jobs--more than 10% of its total work force. But an Eastern spokeswoman in Miami said attrition, early retirement plans and other measures had allowed the airline to limit actual layoffs. Of the jobs eliminated, 1,500 were non-union positions, including management and clerical, airline officials said. Eastern eliminated 12% of its routes two weeks ago, ending service to 14 cities.