"Switched at Birth" actress Marlee Matlin called out Delta airlines on Twitter for its lack of accessibility for deaf and hard-of-hearing passengers, drawing attention to the challenges those with disabilities undergo while traveling.

"Sad to see that my preferred airline, Delta Flight 1998 has provisions for various languages and audio description for in-flight entertainment but no closed captions for deaf and hard of hearing flyers," Matlin, who is the only deaf performer to have won an Academy Award, tweeted Thursday with the hashtags #noaccess and #ADACompliance.

Sad to see that my preferred airline, @Delta flight 1998 has provisions for various languages and audio description for in-flight entertainment but no closed captions for deaf and hard of hearing flyers. #noaccess #stillwaiting for #ADAcompliance pic.twitter.com/CXnmqbHSDB — Marlee Matlin (@MarleeMatlin) December 26, 2019

Her tweet, which has received more than 39,000 likes as of Friday afternoon, drew support from disability advocates.

"Marlee Matlin is a champion for captioning in all areas including on airlines, and we appreciate her efforts to bring public awareness to the lack of full accessibility on airplanes," Howard A. Rosenblum, chief executive officer and director of legal services of the National Association of the Deaf (NAD), an advocacy organization for the deaf and hard of hearing, wrote in an emailed statement.

Delta did not respond to NBC News' request for comment, but it states on its website that it has an advisory board on disability that provides "recommendations to Delta related to compliance, training, policies, procedures and anything that impacts the travel experience of people with different disabilities who are Delta Frequent Flyers."

As for its in-flight entertainment, some of Delta's movies have closed captioning according to its website, by it's not immediately clear which entertainment this applies to. According to a 2018 tweet from Delta in response to another customer questioning whether there were closed captions available in the seatback entertainment systems, the airline said its aircrafts "equipped with the newer IFE system have closed captioned (CC) movie options," but closed captioning is "not available" for live television feeds.

Others responding to Matlin's tweets seemed to corroborate this, by stating that she appeared to be watching a news program, for which captions are not available.

"I am a frequent flyer of @Delta and they do have captions for in-flight entertainment for movies but not live television," wrote one user in response to Matlin.

@Delta - Are there no closed captions or subtitles available in the seatback entertainment systems? Noticed I can’t find it on live tv. — Marcus McCray (@marcusmccray) October 1, 2018

@MarleeMatlin, I am a frequent flyer of @Delta and they do have captions for in-flight entertainment for movies but not live television.



If you want movies, you'll have to select to see what movies are captioned from a drop down menu. — Jared A. (@JaredAllebest) December 26, 2019

The Americans with Disabilities Act of 1990, which Matlin referred to in her tweet, provides civil rights protections to people with disabilities. Though the ADA guarantees individuals with disabilities equal rights to transportation, among other rights, it does not regulate air travel. Instead, another law, the Air Carrier Access Act (ACAA), prohibits discrimination on the basis of disability on airlines.

According to the Department of Transportation, ACAA stipulates that airlines cannot refuse transportation on the basis of disability nor can they require advanced notice that a person with a disability is traveling. Airlines must also have accessible facilities, according to the law, including sufficient space for wheelchairs and other assistive devices. In 2013, the U.S. Department of Transportation (DOT) amended the ACAA to require U.S. air carriers and foreign air carriers to make their websites that market air transportation to the general public in the United States accessible to individuals with disabilities. Though the legislation does not specifically name closed captions on flights as a required provision, it does state that there should be "accommodations" for people with hearing impairments.

"The NAD has for decades advocated for new regulations and/or laws to mandate captioning on airplanes, as the Air Carrier Access Act lacks provisions to require captioning," Rosenblum wrote.

However, according to Rosenblum, such efforts have remained largely stagnant since 2016, when the DOT established the Advisory Committee on Accessible Air Transportation, which included disability advocacy organizations, airlines, aircraft manufacturers and content providers. After seven months of negotiations, the committee reached an agreement that all new in-flight entertainment systems must be capable of supporting closed captions. The agreement also mandated that aircrafts with inaccessible seatback in-flight entertainment systems must provide an alternative personal entertainment device (PED) with accessible comparable video content.

"Despite this agreement, the DOT has not followed through on any rulemaking that was to happen as a result of the agreement," Rosenblum wrote. "Consequently, there is no mandate for airlines to caption their videos."

A spokesperson for the DOT told NBC News that current disability regulation requires airlines to provide captioning of informational and safety videos and that it plans to issue guidelines that would guarantee that in-flight entertainment is accessible to passengers with disabilities.

Closed captioning technology for deaf and hard-of-hearing passengers started in 2008 with Emirates Airlines. Such captions have not only benefitted those who have difficulty hearing, but have made video watchable on silent mode and improved content retention and engagement.

Disability advocates have long taken to social media to request accessible facilities and resources on flights. In 2015, Nyle DiMarco, the second male winner and the first deaf winner of "America's Next Top Model" called on American Airlines to institute closed captions.

"@AmericanAir, your movies did not have subtitles for me as a Deaf person," DiMarco wrote. "It is 2015. When are you going to be 100% accessible for all?"

.@AmericanAir, your movies did not have subtitles for me as a Deaf person.



It is 2015.

When are you going to be 100% accessible for all? — Nyle DiMarco (@NyleDiMarco) November 24, 2015

While a number of airlines, including American Airlines, have at least some captioned entertainment content, Rosenblum said there was no reason to not have captions available for all programs.

"Captioning files exist for EVERY television program and movie that they show on airplanes," Rosenblum wrote. "There is absolutely no reason for any video to be shown on airlines without captioning given the fact that all such videos have captioning elsewhere on the ground."