The union, which represents around 50,000 flight attendants working for airlines including United , Hawaiian , Alaska and Spirit , has been pushing airline executives to ensure safe work environments for flight attendants, who say they are routinely subjected to such behaviors from passengers.

Sixty-eight percent of flight attendants have been sexually harassed at some point in their careers, the Association of Flight Attendants said Thursday, citing a recent survey of members.

Flight attendants are subjected to "rampant" sexual harassment on the job, a survey by the world's largest flight attendant union found.

More than a third of 3,568 respondents to the survey, which the union conducted from February to March, said they experienced verbal sexual harassment by passengers in the past year. Nearly 70 of those respondents said they were sexually harassed three or more times.

"Flight attendants describe the verbal sexual harassment as comments that are 'nasty,

unwanted, lewd, crude, inappropriate, uncomfortable, sexual, suggestive, and dirty,'" said the union. "They also report being subjected to passengers' explicit sexual fantasies, propositions,

request[s] for sexual 'favors' and pornographic videos and pictures."

Eighteen percent of the respondents said they received unwanted physical sexual conduct from passengers, including "having their breasts, buttocks and crotch area 'touched, felt, pulled, grabbed, groped, slapped, rubbed, and fondled' both on top of and under their uniforms," the union added. "Other abuse included passengers cornering or lunging at them followed by unwanted hugs, kisses and humping."

"This is a silent epidemic," said Sara Nelson, president of the union and a career flight attendant. These behaviors often do "not leave physical marks. It's not the same as being punched in the face."

The union said the most common response to such behaviors was to diffuse the situation or ignore the harassment. Only 7 percent of respondents who said they suffered the abuse said they reported the incident.

Nelson said part of the problem is that airlines for decades had marketed flight attendants "as sexual objects." A National Airlines "Fly Me" advertising campaign in the early 1970's featured flight attendants stating their names with the slogan, such as "I'm Cheryl. Fly me."

Nelson said airlines need to establish clear policies for when a crew member is sexually harassed or assaulted.

Lawmakers are starting to address the issue. A recently passed Federal Aviation Administration bill calls for the creation of a group to develop enforcement actions for sexual misconduct on board and establish employee training.

Late last year, United CEO Oscar Munoz called for "zero tolerance" of sexual harassment following reports that Randi Zuckerberg, a media executive and sister of Facebook founder and CEO Mark Zuckerberg, reported she was sexually harassed while a passenger on an flight.