Volkswagen aims to sell more than half a million cars in the United States for the first time in 39 years, the company said on Sunday, building on its last year's global volume that topped the 8 million mark.

The German automaker wants to sell 10 million vehicles world wide by 2018, compared with nearly 8.16 million in 2011 -- not including another 59,000 commercial trucks from Swedish unit Scania .

A tenth of the mid-term volume target should stem from the U.S. market, where it is making strides with the new Beetle and the Tennessee-built Passat mid-size sedan that was recently voted Motor Trend Car of the Year.

Volkswagen had U.S. group sales of 444,192 vehicles last year, a 23.3 percent increase from 2010, with about 70 percent coming from its Volkswagen brand and the remainder from its other brands such as Audi , Bentley and Lamborghini.

Jonathan Browning, chief executive of Volkswagen Group of America, forecast the size of the U.S. car market at between 13.5 million and 14 million vehicles in 2012, depending on economic conditions.

Volkswagen still incurs losses in the U.S. market, but that is now due only to the upfront $1 billion investment in its new Chattanooga plant, which it expects will be profitable once it builds 150,000 cars from next year.

Browning said the national sales operations at the VW brand would achieve an operating profit for the second straight year in 2012.

Speaking later at an evening event in Detroit ahead of Monday's start to the North American International Auto Show, VW Chief Executive Martin Winterkorn said the management was still considering merging majority shareholder Porsche SE

into Volkswagen.

The intention still stands, he told reporters.

Most analysts believe last year's decision to delay the merger meant VW would choose instead to buy the remaining 51 percent of Porsche SE's sports car business outright.

For investors in the listed entity Porsche SE, this would reduce the company to a financial holding that markets usually value at a discount to its net asset value.

(Reporting by Christiaan Hetzner and Jan Schwartz; Editing by Bernard Orr and Vinu Pilakkott)