The alleged 2016 incident - as told to Business Insider by a friend of the accuser, is said to have occurred during a private flight to London in late 2016. Musk is accused of exposing his erect penis to the woman, rubbing her leg without consent, and offering to buy her a horse if she gave him an erotic massage and "do more," implying the performance of sex acts, according to a declaration by the flight attendant's friend.

Two years later, Musk, SpaceX and the attendant entered into a $250,000 agreement in which she agreed not to sue, and to sign non-disclosure and non-disparagement clauses.

Musk called the allegation a "politically motivated hit piece" which "should be viewed through a political lens."

"This is their standard (despicable) playbook," Musk added.