From sustainable fuels to trip reductions: A guide to greener flying

As pandemic restrictions ease and we emerge from lockdown, one thing is resurfacing in the minds and budgets of many: travel.

If the current travel chaos is any indication, we're all eager for a vacation. However, there's a catch – the climate crisis is still very much with us. While two years of staying home has helped reduce our carbon footprints, resuming extensive travel is a step backward for the environment.

The solution, of course, is simple: stop traveling. Or at least, cut back on flying.

But despite the growing flight-shaming movement, it's not an option for everyone. Even if you're not ready to make that sacrifice, there are smaller steps you can take to make your travel more sustainable.

Why is flying such a big issue?

Aviation is responsible for just 2.1% of global human-made carbon emissions, according to the Air Transport Action Group, and % of overall planet-warming emissions. It might not seem that alarming at first glance.

However, as Matteo Mirolo, aviation policy officer at Transport & Environment, a European organization advocating for cleaner transportation, explains, the situation is more complicated.

“You have to consider the growth of the aviation industry. It’s been substantial, even with the impact of Covid,” Mirolo remarked. “After events like 9/11 or the 1970s oil crisis, aviation bounced back stronger. Now, it’s expanding again, and it remains largely unregulated.”

“If we don’t take action now, in a few years, aviation could become one of the biggest contributors to climate change. We shouldn’t focus on the current state, but on the future projections,” he added.

Mixed news ahead

The optimistic news? “There are plenty of solutions” on the horizon, Mirolo noted.

The downside? These solutions aren’t ready yet, with meaningful impact expected to take “decades” to materialize.

Sustainable aviation fuel (SAF) is seen as a potential gamechanger for the future, Mirolo said. However, not all SAFs are equal. What he refers to as 'genuine waste residue' – like the used cooking oil that Airbus recently used to fuel an A380 – represents 'a true step forward.' Synthetic kerosene is also a viable option. But some SAFs use palm oil, which is associated with deforestation. In 2021, Indonesia even conducted a biofuel-powered test flight with palm oil, highlighting the government’s push to boost palm oil-based biofuels.

Neste, a biofuel company supplying SAF to major airlines like American Airlines, KLM, Lufthansa, and Delta, uses palm oil in its non-SAF biofuels. However, a company representative stated that they source it sustainably and plan to phase it out by 2023. According to Mirolo, using palm oil as fuel is 'a cure worse than the disease.'

Although trials are underway with planes running on used cooking oil, it will be decades before this technology becomes commercially viable. The UK government, for example, has proposed that by 2030, all planes refueling in the country must use up to 10% SAF, with that figure rising to 75% by 2050. The EU is considering a 2% SAF mandate by 2025 for flights departing from its airports, while Japan is aiming for a 10% SAF share by 2030.

So far, these claims remain unverified. The only countries with confirmed SAF mandates are Norway, Sweden, and France, where airlines are required to use 1% SAF for flights departing from their airports.

Hydrogen-powered planes might be a reality by the 2030-35 period, but even with that optimistic timeline, these planes will only be capable of flying routes shorter than 2,000 miles, making them unsuitable for long-haul travel, Mirolo noted.

Battery-powered aircraft are unlikely to be ready by 2030, Mirolo said, and like hydrogen planes, they won’t be able to handle long flights. Currently, a 100-seat battery plane can only fly for about an hour. Furthermore, we’ll need to consider the environmental impact of producing and disposing of batteries – they may not be as eco-friendly as expected. Mirolo suggests that hydrogen and electric planes could meet around 20% of passenger demand by 2050, which is why he believes SAF remains the best option.

Mirolo cautioned against airlines promoting their carbon offset programs, labeling them as a red flag. 'Carbon offsetting was trendy a few years ago, but it’s not the solution – SAF is,' he said.

Mike Childs, head of science, policy, and research at Friends of the Earth, previously called carbon offsetting a 'massive con' in an interview with Dinogo, pointing out that the benefits are either long-term (and uncertain) or based on efforts that are already underway, like reforestation. 'Nothing has fundamentally changed' in the offsetting schemes, he added.

The key takeaway: Fly less

Experts recognize that, realistically, most people will still need to fly from time to time. As Childs wisely put it: 'None of us are perfect.'

This isn’t about whether flying should be banned, but rather how we can reduce the carbon emissions that come from it,” said Justin Francis, CEO of Responsible Travel, which offers sustainable travel options worldwide.

Francis believes that travel expands our horizons and supports local economies, but he argues that many of us are overdoing it. Instead of seizing every flight deal that pops up, he suggests we return to the mindset where flying was a special event.

Experts urge us to change our mindset about flying. Childs emphasizes that we should consider flying as a last resort. 'The best alternative is often taking the train, or, in many cases, driving is a better option, mile for mile,' he said.

Mirolo advises that every time we plan a trip, we should 'think twice before flying.' Can another mode of transport get us there? If it's a business trip, is meeting face-to-face really necessary, or can we handle it remotely? 'It’s not about eliminating flying, just making more thoughtful choices,' he said.

'Our approach is to encourage longer vacations, which would reduce the total number of flights,' explained Francis. 'Taking a longer trip is often more relaxing and enjoyable, and we must keep carbon emissions in mind. Big trips should be chosen carefully, and we should look to alternative transport for shorter journeys.'

'For me, instead of flying long-haul twice a year, I might still visit Vietnam, but for one of my longer journeys, I could take a slow travel train to Italy instead,' said Francis.

Trains and buses

Of course, Francis has the advantage of living in Europe, where high-speed trains are common. But even in places with less public transport, like the US, Childs argues it's still better to skip the flight and opt for other modes of travel.

He believes that a long US road trip, such as from Washington, DC to Yellowstone National Park, would have a smaller environmental impact than a quick flight to the Caribbean.

If train or public transport options aren’t available, and you have to choose between driving and flying, driving is always the more environmentally friendly choice,” he said. “It’s much easier to move a vehicle full of passengers on the ground than to get a plane off the ground and keep it there... In the future, we might see greener flying alternatives for short distances, but for now, stick to surface transport whenever possible.

The more frequently surface transport is public, such as with trains and buses, the better it is for the environment.

How to fly

For those who’ve experienced the luxury of business class, returning to economy can feel like a downgrade. However, economy is the most eco-friendly option for flying – and budget airlines that maximize seat capacity are the most fuel-efficient.

In February 2022, premium seats accounted for only 5% of international flights, according to the International Air Transport Association. Yet, these seats take up significantly more space. For example, Wizz Air, which has an all-economy configuration, fits 239 seats on its A321neo, whereas its competitor Lufthansa, which includes business class, configures the same aircraft with only 215 seats. The difference is similar for the A320-200, with Wizz Air squeezing 186 seats and Lufthansa fitting just 168.

On shorter flights, the main difference between business and economy is a bit more space and comfort, like wider seats or extra legroom. But for long-haul flights, the situation changes dramatically, with business class featuring fully reclining beds and even private suites on airlines like Emirates and Singapore Airlines, which take up the equivalent of several rows of economy seats.

Singapore Airlines and Emirates both operate the A380, but with different layouts. Singapore Airlines places both economy and premium economy on the top deck, fitting 399 passengers. Meanwhile, Emirates reserves the top deck exclusively for business and first class, accommodating just 90 passengers in the same space.

Business and first class seats are also much heavier, with fixed, shell-like seats and sometimes even enclosed doors for added privacy.

Budget airlines are considered greener – at least on paper.

Wizz Air, a European budget carrier, touts itself as the ‘greenest’ airline on the continent. They credit their young, fuel-efficient fleet, high-density, all-economy seating, and direct-only flight policy for their low carbon footprint. Additionally, they only fly routes where there are no rail alternatives within four hours. Wizz claims to have the lowest CO2 emissions per passenger kilometer in Europe and encourages passengers to fly only when necessary.

However, this claim doesn’t tell the full story, according to Mirolo. While low-cost carriers like Wizz Air have good emissions metrics per passenger, their rapid growth makes them a key factor in the aviation industry’s unsustainable expansion.

When it comes to legacy carriers, the problem lies in long-haul flights, which account for just 5% of flights but represent 50% of aviation emissions. The EU's proposed SAF mandate will apply only to flights departing from EU airports, meaning it will cover intra-EU flights but not half of the long-haul routes, such as those leaving the EU but not returning.

Mirolo suggests that passengers who care about sustainability should actively choose airlines that are investing in and using SAF in a credible manner. Airlines like United, Alaska, Qantas, and SAS, which even allow passengers to purchase biofuel ‘blocks’ alongside their flights and earn extra miles in return, are examples of such carriers.

Air France-KLM is subject to the 1% SAF mandate for flights departing France. However, since January, they've also committed to using 0.5% SAF on all planes flying from their Amsterdam Schiphol hub. A small surcharge (€1-€10) is added to tickets to cover this.

Mirolo encourages passengers to use their voting power to push for a more sustainable aviation sector. With the political will to make sustainable aviation a reality stronger than ever, he urges people to vote with their ballots and their travel choices.

Private jets are notoriously damaging to the environment, but there is a potential upside. Their technological advancements could, in the future, help accelerate progress toward greener aviation practices.

For many of us, the closest we’ll get to flying privately is by watching celebrities on social media. But despite being a luxury reserved for the wealthy, private jet travel still has significant environmental impacts.

A 2021 report from the environmental group Transport & Environment found that just 1% of people account for half of all global aviation emissions. Meanwhile, the private jet sector has grown by 31% between 2005 and 2019. In addition, 40% of private flights are 'ghost flights,' where the plane is empty while repositioning for its next journey.

Private jets are even more environmentally damaging due to their frequent short flights. For most of Europe’s most popular private jet routes, there’s a viable train alternative. Mirolo noted that in France, 10% of all flights are private jets.

The advantage of private jets lies in their smaller size, which positions them to quickly adopt new technologies as they become available. This agility could accelerate advancements in the aviation sector.

"The ultra-wealthy have the power to accelerate the decarbonization of aviation by backing electric and hydrogen-powered aircraft," said Mirolo. By doing so, the wealthiest 1% could make air travel more sustainable for everyone.