Abigail Disney, a documentary filmmaker and philanthropist, is also well-known for her social activism, including her takedowns of generational wealth, charitable support for women leaders, and even criticisms of the media empire founded by her great-uncle Walt Disney (although she is still a shareholder).

The latest subject of Abigail Disney’s attention is one that many social and environmental activists targeted relentlessly last year: rich people flying private jets.  

“Private jets are a cancer. I’m sorry, and I know and love lots of people who ride around in them,” Disney wrote in a Twitter post Sunday, adding that while she understood that some very wealthy people fly private because of concerns for their privacy, they could also fly business class on a commercial flight instead.

“I also occasionally fly biz class, and I fail to see what is so hard about that,” she wrote.

Celebrities and public figures including Kylie Jenner, Taylor Swift, Elon Musk, and Drake were targeted by online sleuths last year who set up groups on the internet dedicated to tracking down their private jets’ movements and emissions. By one estimate, during the first seven months of 2022 celebrities emitted 480 times more greenhouse gas with their plane flights alone than the average person generates over an entire year.

Disney, writing from a business class seat as she traveled back home from Rome, urged wealthy private jet owners to think about what they could do to alleviate the climate crisis enveloping the planet and “come fly with the rest of us,” saying behavioral changes from celebrities and public figures would be “tantamount to thousands, even hundreds of thousands” of other people making adjustments.

The media heiress has recently taken climate issues to heart, penning a CNN op-ed in November criticizing billionaires for their extravagant and climate-costly habits while citing recent Oxfam research that found the investments of the world’s 125 richest people generated a million times more emissions than the average person sitting in the bottom 90% of global wealth.

Disney has for years used her position and her name to urge the wealthiest strata of society to behave more conscientiously. In 2019, she called Disney CEO Bob Iger’s $65.6 million salary “insane” for being hundreds of times larger than that of the average Disney employee. In an interview with Fortune‘s Maria Aspan last year, Disney emphasized how the “troubling” divergence between worker and CEO pay was only getting “more and more dramatic.”

In 2019, during an interview with The Cut, she said she has donated around $70 million of her personal wealth since she turned 21. During the same interview, she said she would support “a law against private jets, because they enable you to get around a certain reality.”

Disney’s opposition to standards of generational wealth was encapsulated in another 2019 interview, with the Financial Times, where she said she aspired to become a “traitor to her class,” while disclosing her net worth of around $120 million.

Disney’s advice to billionaires to fly commercially instead of private came with a caveat, as flying business class takes up more space on a plane and leads to higher individual emissions than flying coach. A 2010 analysis from the Guardian found that on an average long-haul British Airways flight, emissions more than tripled between economy and business class passengers. A 2013 World Bank study found that booking an economy class ticket is the most environmentally friendly option to fly, while first class tickets generate seven times as many emissions.  

Disney admitted in her Twitter post that she does feel guilty for flying business instead of coach, and pledged to start the new year by taking up the most environmentally friendly flying option there is: staying at home.

“For 2023 I’m cutting back on all of it,” she wrote, adding that she will log on to more meetings virtually and travel by train where possible. “I’m weighing every trip against my personal cost/social benefit measure, from here on out.”