By Bernie Woodall CHATTANOOGA, Tennessee (Reuters) - Volkswagen AG will add 800 jobs at its only U.S. plant to increase production of the Passat sedan, the company said on Thursday. The new hires will be added to the Chattanooga plant's existing workforce of 2,200 Volkswagen workers and another 500 who work for a contract firm called Aerotek. The plant will not add another shift, but will place a third "team" of workers on the existing two shifts and add a Saturday shift to accommodate the additional production, said Hans-Herbert Jagla, head of human resources at the factory. Plant manager Frank Fischer said there are thus far no plans for a second model to be produced at the Chattanooga plant, which opened in May 11. Jonathan Browning, head of VW operations in North America, said the plant's additional production will bring its annual capacity to 170,000 vehicles, up about 20,000 from current capacity. In its ramp up year of 2011, the plant produced about 40,000 Passats. He said 25 percent of all Volkswagens sold in the United States are Passats made in Chattanooga. Browning said that soon VW is likely to announce an increase of its forecast for industry-wide U.S. auto sales in 2012 to 14 million vehicles from its current forecast of 13.7 million vehicles, based on stronger-than-expected first-quarter sales for the industry. In the first two months of the year, Volkswagen sold 14,500 Passat sedans in the U.S. market. Last year, Volkswagen's U.S. sales increased 26 percent to about 325,000 vehicles for the VW brand. Including its Audi luxury brand, the VW Group sold about 450,000 vehicles in the U.S. market in 2011. VW has said it will sell more than 500,000 vehicles, including Audi models, in 2012, and wants to increase its U.S. sales to 1 million vehicles by 2018. VW has a target of selling 10 million vehicles globally by 2018, up from 8.3 million in 2011. Reporting By Bernie Woodall; Editing by Gerald E. McCormick, Dave Zimmerman