That story seems apocryphal. Richard Branson's business empire started with Virgin Records (and in particular, signing Mike Oldfield before Tubular Bells became a huge hit), and the name came from him sitting around stoned at a party/orgy with a bunch of friends and saying, "Well, we're all virgins in business, so let's just call it Virgin Records." He's not a cofounder of Virgin Atlantic - the cofounders were Randolph Fields and Alan Hellary, and Randolph met RB at a party in which RB agreed to put up all the money in exchange for a large equity stake. He was already wealthy from the success of Virgin Records, which had been in business for a decade.

Sources: Losing My Virginity (Richard Branson's autobiography) and the Wikipedia page on Virgin Atlantic:

https://en.wikipedia.org/wiki/Virgin_Atlantic