Now playing
04:39
CNN uncovers sexual assaults on flights (2017)
CANNES, FRANCE - MAY 26: Actress Asia Argento attends the 'Zulu' Premiere and Closing Ceremony during the 66th Annual Cannes Film Festival at the Palais des Festivals on May 26, 2013 in Cannes, France. (Photo by Pascal Le Segretain/Getty Images)

LOS ANGELES, CA - FEBRUARY 21: Actor Jimmy Bennett arrives at the premiere of Relativity Media's '21 And Over' at the Village Theatre on February 21, 2013 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)
Getty Images
CANNES, FRANCE - MAY 26: Actress Asia Argento attends the 'Zulu' Premiere and Closing Ceremony during the 66th Annual Cannes Film Festival at the Palais des Festivals on May 26, 2013 in Cannes, France. (Photo by Pascal Le Segretain/Getty Images) LOS ANGELES, CA - FEBRUARY 21: Actor Jimmy Bennett arrives at the premiere of Relativity Media's '21 And Over' at the Village Theatre on February 21, 2013 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)
Now playing
02:30
Asia Argento reportedly paid assault accuser
NBC's "Megyn Kelly Today"
Now playing
01:35
McGowan to Weinstein: We got you
Mike Windle/Getty Images for Venice Family Clinic
Now playing
07:46
New Yorker: 6 women accuse CBS CEO of sexual harassment
PASADENA, CA - JANUARY 09:  Chris Hardwick attends the 2018 NBCUniversal Winter Press Tour at The Langham Huntington, Pasadena on January 9, 2018 in Pasadena, California.  (Photo by Christopher Polk/Getty Images)
Christopher Polk/Getty Images
PASADENA, CA - JANUARY 09: Chris Hardwick attends the 2018 NBCUniversal Winter Press Tour at The Langham Huntington, Pasadena on January 9, 2018 in Pasadena, California. (Photo by Christopher Polk/Getty Images)
Now playing
00:50
TV host returning after abuse allegations
NBC/"Today"
Now playing
01:17
Robin Wright on Kevin Spacey: We were saddened
LOS ANGELES, CA - FEBRUARY 13:  Executive producer/actor Kevin Spacey arrives at the special screening of Netflix's "House of Cards" Season 2 at the Directors Guild Of America on February 13, 2014 in Los Angeles, California.  (Photo by Kevin Winter/Getty Images)
Kevin Winter/Getty Images
LOS ANGELES, CA - FEBRUARY 13: Executive producer/actor Kevin Spacey arrives at the special screening of Netflix's "House of Cards" Season 2 at the Directors Guild Of America on February 13, 2014 in Los Angeles, California. (Photo by Kevin Winter/Getty Images)
Now playing
01:27
The sexual assault claims against Kevin Spacey
CSPAN
Now playing
01:55
Actor on sexual assault: He held the power
NEW YORK, NY - JUNE 20:  Chef Mario Batali arrives at EAT (RED) Food & Film Fest! at Bryant Park on June 20, 2017 in New York City.  (Photo by Michael Loccisano/Getty Images for (Red))
Michael Loccisano/Getty Images North America/Getty Images for (Red)
NEW YORK, NY - JUNE 20: Chef Mario Batali arrives at EAT (RED) Food & Film Fest! at Bryant Park on June 20, 2017 in New York City. (Photo by Michael Loccisano/Getty Images for (Red))
Now playing
02:45
NYPD investigating Mario Batali for sexual misconduct
Mike Coppola/Getty Images
Now playing
00:49
Tom Brokaw facing sexual harassment allegations
LOS ANGELES, CA - JUNE 16:  Actress Bella Thorne attends the Babes for Boobs Bachelor Auction benefitting the Los Angeles County Affiliate of Susan G. Komen on June 16, 2016 in Los Angeles, California.  (Photo by Matt Winkelmeyer/Getty Images for Babes For Boobs)
Matt Winkelmeyer/Getty Images North America/Getty Images for Babes For Boobs
LOS ANGELES, CA - JUNE 16: Actress Bella Thorne attends the Babes for Boobs Bachelor Auction benefitting the Los Angeles County Affiliate of Susan G. Komen on June 16, 2016 in Los Angeles, California. (Photo by Matt Winkelmeyer/Getty Images for Babes For Boobs)
Now playing
00:54
Former Disney actress reveals sexual abuse
ZURICH, SWITZERLAND - SEPTEMBER 22:  Harvey Weinstein attends the 'Lion' premiere and opening ceremony of the 12th Zurich Film Festival at Kino Corso on September 22, 2016 in Zurich, Switzerland. The Zurich Film Festival 2016 will take place from September 22 until October 2.  (Photo by Andreas Rentz/Getty Images)
Andreas Rentz/Getty Images
ZURICH, SWITZERLAND - SEPTEMBER 22: Harvey Weinstein attends the 'Lion' premiere and opening ceremony of the 12th Zurich Film Festival at Kino Corso on September 22, 2016 in Zurich, Switzerland. The Zurich Film Festival 2016 will take place from September 22 until October 2. (Photo by Andreas Rentz/Getty Images)
Now playing
01:10
Weinstein empire unravels amid scandal (2017)
CNN
Now playing
03:21
Japan accused of failing sexual abuse survivors
Former Michigan State University and USA Gymnastics doctor Larry Nassar listens during the sentencing phase in Eaton, County Circuit Court on January 31, 2018 in Charlotte, Michigan. Last week Nassar was sentenced in Ingham County to 40 years to 175 years in prison.
The number of identified sexual abuse victims of former USA Gymnastics doctor Larry Nassar has grown to 265, a Michigan judge announced Wednesday as a final sentencing hearing commenced. Prosecutors said at least 65 victims were to confront Nassar in court, in the last of three sentencing hearings for the disgraced doctor who molested young girls and women for two decades in the guise of medical treatment.
 / AFP PHOTO / JEFF KOWALSKY        (Photo credit should read JEFF KOWALSKY/AFP/Getty Images)
JEFF KOWALSKY/AFP/AFP/Getty Images
Former Michigan State University and USA Gymnastics doctor Larry Nassar listens during the sentencing phase in Eaton, County Circuit Court on January 31, 2018 in Charlotte, Michigan. Last week Nassar was sentenced in Ingham County to 40 years to 175 years in prison. The number of identified sexual abuse victims of former USA Gymnastics doctor Larry Nassar has grown to 265, a Michigan judge announced Wednesday as a final sentencing hearing commenced. Prosecutors said at least 65 victims were to confront Nassar in court, in the last of three sentencing hearings for the disgraced doctor who molested young girls and women for two decades in the guise of medical treatment. / AFP PHOTO / JEFF KOWALSKY (Photo credit should read JEFF KOWALSKY/AFP/Getty Images)
Now playing
01:58
Nassar survivor: 'Have fun in prison'
allegations against Al Franken orig me_00000000.jpg
allegations against Al Franken orig me_00000000.jpg
Now playing
02:34
The allegations against Al Franken (2017)
TODAY -- Pictured: Matt Lauer on Friday, June 30, 2017 -- (Photo by: Nathan Congleton/NBC/NBCU Photo Bank via Getty Images)
Nathan Congleton/NBC/NBCU Photo Bank via Getty Images
TODAY -- Pictured: Matt Lauer on Friday, June 30, 2017 -- (Photo by: Nathan Congleton/NBC/NBCU Photo Bank via Getty Images)
Now playing
01:15
Matt Lauer fired from NBC News
(CNN) —  

A bipartisan group of lawmakers is calling on the leaders of 30 airlines to take action on sexual harassment and assault in the airline industry, saying the problem has been tolerated for too long.

“Flight attendants are first responders to medical emergencies, in-flight fires, or evacuations as well as the last line of defense against hijacking,” the lawmakers write according to a copy of the letter obtained by CNN. “They deserve our respect and gratitude, and to be treated fairly.”

The letter, spearheaded by Democratic Rep. Lois Frankel of Florida and Republican Rep. Barbara Comstock of Virginia, is the latest move to pressure airlines to address sexual harassment and assault in the air, both targeting flight attendants and passengers. CNN reported in December on the increased FBI investigations into in-air sexual assault or harassment, and the lack of training flight attendants receive.

“We are continuing our efforts at creating a culture of zero tolerance for sexual harassment in the workplace and the best practices for ensuring that,” said Comstock.

Asked why the group opted to send a letter rather than pass legislation to force the industry to address sexual harassment, Frankel said: “In my opinion it will be quicker for industry leaders to step up and fix the problem rather than waiting for Congress.”

RELATED: She says a pilot raped her, and now she’s afraid of running into him at an airport

CNN’s December reporting on sexual harassment and assault on airlines focused on the experiences of passengers on commercial flights who said they had experienced sexual harassment or assault.

It is difficult to tell just how frequently these assaults happen because no federal regulatory agency tracks that data nationwide. However, FBI investigations into in-flight sexual assaults increased by 66% from fiscal year 2014 to 2017, CNN reported.

A recent survey conducted by the Association of Flight Attendants found that 68% said they experienced sexual harassment themselves. An equal share said they have not noticed any efforts by their employers over the past year to address sexual harassment on the job.

Sara Nelson, a United Airlines flight attendant who is president of the union, spoke at a Capitol Hill briefing on harassment in the service industry in March and said that flight attendants, who are overwhelmingly women, are “ongoing victims of sexual harassment and sexual assault.”

“In December 2017, after the launch of the MeToo Movement, I publicly called on the airline chief executives to clearly and forcefully denounce the past objectification of flight attendants, reinforce our safety role as aviation’s first responders and pledge zero tolerance of sexual harassment and sexual assault at the airlines,” Nelson told members of the bipartisan caucus. “It is absurd to think that a group of people frequently harassed for decades can effectively become enforcers during emergencies without this level of clarity about the respect we deserve.”