The huge installations United Airlines uses to prepare and cook inflight food recently got a new addition: some television screens. But rather than just providing news or talk show chatter, they broadcast messages explaining why workers shouldn’t unionize.

Employees at all five of United Continental Holdings Inc.’s kitchens in the U.S. said the screens, installed this year, broadcast a company line urging opposition to hospitality union Unite Here, which is seeking to organize its workers, or touting United’s achievements. Among the messages are warnings about the cost of union dues, the potential for workers to lose benefits if they unionize and the difficulty of getting rid of a union once it’s been voted in. The last point, the workers said, is illustrated with the image of a forearm with a “Together Forever” tattoo.

“It’s driving people crazy,” said Maria Villaroel, a 12-year employee who does safety and security inspections at United’s kitchen at Newark International Airport. She said TVs have been broadcasting anti-union messages in the cafeteria, the loading dock and the food production area. “They’re trying to wash people’s brains.”

Now, the union is fighting United’s use of TVs (as seen in the background of a Twitter post featuring airline President J. Scott Kirby) and its allegedly broader campaign against the union—the latest move in an escalating war between them. In a complaint filed Thursday with the National Mediation Board, Unite Here alleged United has illegally prevented employees from engaging in pro-union activity and subjected pro-union employees to surveillance, harassment and retaliation. The complaint, which claims support by 58 sworn employee declarations, also alleges that United officials conveyed “threats, promises, and misinformation through postings and electronic messages in the workplace,” such as the TV screens, and in small group and one-on-one meetings. 

United called the union’s allegations “baseless,” saying it “respects our employees’ rights to decide whether they want to be represented by a union.” 

On May 23, when confronted by employees at a shareholder meeting, Chief Executive Officer Oscar Munoz said United’s job was to “educate” employees about their benefits and how, under collective bargaining, those could be subject to negotiation. “I think it’s important, as you and your fellow peers make decisions around that decision, that you’re aware of the things that do come up,” he said.

Unlike its competitors, United directly employs 2,700 kitchen workers who prepare and transport food for flights. They are the only group of frontline United employees who, unlike flight attendants, pilots, baggage handlers and mechanics, don’t have union representation. Pro-union kitchen workers said they sought to organize to address issues including what they see as the company’s overly restrictive attendance policy, which workers claimed causes them to report to work when they’re sick.

United countered that its kitchen workers get more paid vacation days than their counterparts at contractor Gate Gourmet. A spokesperson also alluded to the possibility of jettisoning in-house kitchens, inherited from its merger with Continental, altogether. 

But if United were to turn to Gate Gourmet or LSG Sky Chefs for inflight food service, it would also find Unite Here: The union represents employees at both of those companies. 

Unite Here filed its unionization petition in January with support from three-quarters of the United kitchen workforce, which would usually trigger a National Mediation Board-supervised election. United, however, responded by filing a complaint with the NMB alleging fraud and misrepresentation by the union. In a rare move, the board, which is led by a 2-1 Republican majority appointed by President Donald Trump, chose to indefinitely delay the union vote while investigating the airline’s allegations, all of which Unite Here denied.

Democrats in both houses of Congress and legislators in five states where United has kitchen facilities sided with the union, urging Munoz to instead examine alleged misconduct by his own managers.

In the past, union leaders including Sara Nelson, president of the Association of Flight Attendants, supported Munoz, who has weathered repeated public relations crises, many tied to the mistreatment or physical assault of passengers. In a January letter to Munoz supporting Unite Here, leaders of the AFA, the Air Line Pilots Association, the International Association of Machinists and Aerospace Workers and the Teamsters credited the CEO with building “positive labor relations” since taking the helm in 2015. The unions told Munoz in a joint letter that the catering workers’ campaign for collective bargaining “is an important opportunity to lift up thousands of United’s lowest-paid employees.”

But United has been under acute pressure from investors to boost profits, and last year nixed plans for Munoz to ascend to the post of chairman. In October, after he asked during an earnings call for “more patience” from investors, United’s stock fell the most in eight years, and analysts reported queries from investors about whether it was time for new leadership. And the bad news is still rolling in: This week United finished last among traditional carriers in J.D. Power’s 2018 airline satisfaction study for North America. 

“The investor base is really looking for United to close their profit gap with Delta and American,” said George Ferguson, a senior aerospace analyst for Bloomberg Intelligence. “So anything that would work against that, like higher wages to any labor group, is going to be difficult.” 

A United spokesman said the airline’s push for an NMB investigation of the union’s behavior wasn’t related to bottom line pressures. The kitchen facility televisions, meanwhile, are part of a standard practice to share information with all employees, he said. “United Airlines is committed to treating all of our employees fairly,” the company said, whether or not they are represented by a union.

Pro-union employees disagree. They argue that by resisting their organizing efforts, United is trying to deprive them of the benefits their co-workers in better-respected jobs already enjoy. “United treats us almost as an unwanted stepchild,” said David Guerrero, a 55 year-old driver for the airline’s Houston kitchen who said he makes about $14.75 an hour.

Guerrero said he felt intimidated working in a facility with a trio of TV screens displaying anti-union messages, including warnings that if workers unionized they might not keep getting discount flights. His counterpart, Annich Sperlich, said that in the facility where she works in Cleveland, a TV screen in her small break room blares anti-union audio and visuals. “There were days that you would be sitting in there and that’s all you could hear,” she said.

Teresita Felix, a pro-union United food production worker in Denver, said she has been fielding questions from co-workers who, after seeing the anti-union TV screens, asked her things like “why are you really fighting for this, when they’re going to take away our benefits?”