During the debate over the recent tax overhaul bill, Democrats scrutinized an alleged “private jet tax break” that was snuck into the legislation. Sometimes nicknamed “PJ” in Top 40 hits, private jets have long symbolized fame, wealth and glamour. On social media, Instagram stars and celebrities upload guache selfies in private jets on a daily basis. Though they remain immensely popular, with an upwards of 12,051 registered in the US alone, there’s a growing chorus of environmental criticism.

As Silicon Valley companies and Hollywood celebrities push for a greener and more sustainable future, the continuous ubiquity of private jets remains an outlier. Environmentally friendly public figures like Leonardo DiCaprio and Elon Musk have been labeled hypocrites for still flying private. But is there a way to make private jets better for the environment? Or is time to retire the private jet altogether?

Often, broad academic statistics don’t illustrate the unique impact that specific technologies have on the environment. When considering private jets’ effects on the macro level, they seem excessive but not particularly harmful. Still, when delving into how they impact local communities, their detrimental aspects are crystallized. Dr. Pedro J.J Alvarez, a professor at Rice University’s School of Civil and Environmental Engineering, explains that even if “on a per passenger basis, private jets have a much higher carbon footprint than commercial airlines,” in fact “commercial flights are more common and consume about 10,000 more cumulative total fuel than private flights.” He claims that with recent developments in fuel efficiency, American aviation’s overall impact on the environment has decreased and that one out of eight cars being taken off the road is equivalent to the industry’s entire carbon footprint.

Private jets are an easy target for environmentalists because of their association with elites. As Alvarez suggested, there very may well be more constructive ways to tackle climate change on a broader scale. However, according to Dr. Joseph Lyou, the president of the Coalition for Clean Air, private jets’ detrimental effects manifest on a local level. Lyou says that in the case of private jets, the more efficient the engines have become, the worse their environmental impact. He continues to break down how “the high temperature that [small jet engines] combust fuel, the combustion mixes with oxygen and creates Nitrogen OX.” Nitrogen OX, referred to as NOx, leads to smog and those NOx emissions will only continue to increase. The Los Angeles area—his field of expertise—is infamous for a smog problem that results in 1,300 deaths a year. For the second year in a row, Southern California’s smog levels have increased even with overall reduced emissions.

So, what can be done to this stop negative shifts in air quality? Lyou hopes that both the government and private sector will start investing in research for engines that are both fuel efficient and emit less harmful pollutants. Within the private sector, there has already been small yet inarguably positive developments to make the industry more sustainable. In May of 2016, Jettly, a private jet company based in Ontario, Canada, started a Clean Air Commitment Campaign as an attempt to offset their carbon footprint. As part of their initiative, they donate $10 to the David Suzuki Foundation for each booked flight while CEO Justin Crabbe insists they’re “utilizing technology to reduce the pollution of our planes such as turboprop engines.”

For over ten years, Stratos Jets, an Orlando based company, has been participating in a “Eco-Jet Charter Program“—a partnership with Terra Pass in which they donate one percent of “the total quote” of each flight to initiatives that promote sustainability. Terra Pass offers companies carbon certificates that give funds to research projects to remove methane gasses, convert waste into renewable energy, and make forests absorb higher levels of carbon. One Stratos Jets report claims that through their Eco-Jet Charter program, “35,236lbs of Carbon emissions” had been neutralized in a single month. Despite not entirely solving the issue, they may have found a way to slightly mitigate its negative effects.

Yes, aviation companies like Jettly and Stratos Jets have made genuine strides in promoting sustainability, but we can’t help but be weary. often times, corporate green initiatives can merely be a publicity stunt. In 2008, when Virgin Airlines started experimenting with renewable biofuels, environmental activists pointed the flaws in their efforts, noting how biofuels harmfully rely on crops. Even if private jets companies’ efforts are sincere and can lead to making a dent in emissions levels, in the bigger picture, it might as well be a marketing ploy. In regards to carbon offset programs, Alvarez acknowledged that any “little effort towards a more sustainable future helps” while stressing that there are better ways, like not driving your car, to make up for the impact of air travel. Alvarez says that ultimately, carbon offsets are a “placebo” making customers feel better and more environmentally conscious.

Perhaps private jets will simply go out of style if criticism grows loud enough. Following a backlash to his own private jet usage, Leonardo DiCaprio decided to fly commercial to his environmental foundation’s latest gala in Saint-Tropez. In recent years, high-priced, sustainable brands and resorts have become fashionable for conscious elites. Highways are now peppered with Teslas and BMW hybrids. Eco-friendly brands like Olderbrother, Where Mountains Meet and Sunad have all been featured in Vogue. Luxury is a concept that can be finessed and transformed with ingenious marketing. Hopefully one day, Instagram stars will find a way to show off their wealth that doesn’t contribute to a smog crisis.