The U.S. carrier will buy Singapore Airlines' 49% stake in Virgin Atlantic for $360 mil. As part of the deal, the 2 airlines will form a trans-Atlantic joint venture that will give Delta Air Lines (DAL) more slots at Heathrow Airport. Richard Branson, who will still have a controlling 51% stake in the company, made it clear Mon. that Virgin would keep its brand. Delta shares rose 5.1%.