She said a flight attendant offered to move her to another seat in the back of the plane, but she declined. “Why is it the woman that needs to switch seats in this situation? Shouldn’t he have been thrown off the plane?!” she said.
“We cannot support businesses that are complicit in allowing this behavior, and value the money of harassers over the comfort of their passengers,” she added.
A spokesman for Alaska Airlines said on Thursday that it was “fully investigating” the encounter and that two airline executives had talked to Ms. Zuckerberg about her flight. The passenger’s travel privileges have also been suspended, the airline said.
“What Randi Zuckerberg shared with us is very disturbing,” the spokesman, Ray Lane, said. “We want our guests to feel safe. As a company, we have zero tolerance for any type of sexual misconduct that creates an unsafe environment for our guests and crew members.”
Ms. Zuckerberg updated her Facebook post after she talked to the Alaska Airlines executives. “While it never should have happened in the first place, I am thankful that they are taking the situation seriously,” she said. She did not immediately respond to a request for additional comment.
Cases of sexual harassment, assaults and misconduct on planes are not collected in a centralized database, making it difficult to determine how frequently they occur. The F.B.I. conducted 58 investigations of reported sexual assault on planes from January to September 2016, up from 40 during all of 2015, according to the bureau.
The actual number of assaults was likely far greater, as the majority go unreported.
Andrew J. Maloney, a lawyer who specializes in aviation law, said that based on Ms. Zuckerberg’s account of the episode, Alaska Airlines could be held liable in a lawsuit. He said it appeared the airline failed to protect her from the unruly passenger.
“Passengers have a right to feel secure, and airlines have a legal duty to protect passengers from harassment, especially if they are aware that a passenger is being harassed,” Mr. Maloney said. “Once Ms. Zuckerberg told flight attendants about this man’s behavior, they should have moved him to a different seat or ejected him from the airplane.”