The Virgin Group of Richard Branson is on track to become the world's first commercial spaceline, with suborbital flights for space tourists due to start in 2008, the British billionaire has said. In an interview in Dubai, where his Virgin Atlantic airline began flights from London this week, Branson said other companies offering space travel had not matched the progress made by the Virgin Galactic venture. "A number of companies around the world are offering space travel but they haven't tested and built any space ships. They certainly haven't had test flights into space," Branson said on Wednesday. "Virgin is...