Feb 25 (Reuters) - Billionaire Richard Branson's space tourism company, Virgin Galactic Holdings Inc, said on Tuesday net losses widened to $73 million in the fourth quarter from $46 million in the year-ago period, in its first financial results as a publicly traded company.

The fourth-quarter results come as the money-losing company is aiming for a first flight later this year with Branson on board, while seeking a new source of revenue in thousands of potential space travelers. (Reporting by Eric M. Johnson in Seattle; Editing by Tracy Rucinski)