When an airline no longer wants a plane, it is sent away to a boneyard, a storage facility where it sits outdoors on a paved lot, wingtip to wingtip with other unwanted planes. From the air, the planes look like the bleached remains of some long-forgotten skeleton. Europe’s biggest boneyard is built on the site of a late-30s airfield in Teruel, in eastern Spain, where the dry climate is kind to metallic airframes. Many planes are here for short-term storage, biding their time while they change owners or undergo maintenance. If their future is less clear, they enter long-term storage. Sometimes a plane’s limbo ends when it is taken apart, its body rendered efficiently down into spare parts and recycled metal.

In February, Patrick Lecer, the CEO of Tarmac Aerosave, the company that owns the Teruel boneyard and three others in France, had one eye cocked towards China. Lecer has been in aviation long enough to remember flights being grounded during the Sars epidemic in 2003. This year, when the coronavirus spread beyond Asia, he knew what was coming. “We started making space in our sites, playing Tetris with the aircraft to free up two or three or four more spaces in each,” he told me.

By late March, after the US shut its skies to Europe, planes began streaming into Tarmac Aerosave’s boneyards. No one knew if they were going into short-term residency or long-term storage. On one day alone, 3 April, the Teruel boneyard received five Boeing 747s and two Boeing 777s. Throughout the next few weeks, planes arrived from Lufthansa, Air France, Etihad and British Airways. Before the pandemic, there were 78 aircraft at Teruel. By June, there were 114, running near the full capacity of 120-130. Patrick Lecer’s other three boneyards were also “close to saturation”, he told me in July. He sounded grave. He had just spent two hours on the phone with an airline that wanted him to house another 30 planes. “I’ve been in this business almost 40 years, and I’ve never seen anything like this. The mood is bad. It feels like a tragedy.”

Among all the industries hit by Covid-19, aviation suffered in two distinct ways. Most obviously, there was the fear of contagion. No other business depends on putting you into knee-by-thigh proximity with strangers for hours, while whisking potentially diseased humans from one continent to another. Less directly, there was the tumbling economy. It is an axiom in aviation that air travel correlates to GDP. When people have more money, they fly more. But in the midst of this historic downturn, no one was buying plane tickets.

In the past, airlines have only been stung by one or the other of these factors. During Sars, travel was unsafe, but the global economy didn’t flatline. During the 2008 financial crash, money was tight, but flying was not a health risk. In the 110 years since the dawn of commercial flight, these blows had never been dealt in tandem, until this year.

To customers, investors and airlines, an earthbound existence was unimaginable before the coronavirus. For commercial aviation, the past two decades have been a period of superheated growth. In 1998, airlines sold 1.46bntickets for one kind of flight or another. By 2019, that number had shot up to 4.54bn. This year has undone it all. Early in March, the International Air Transport Association (Iata) published two potential scenarios. The more extreme one forecast a global loss of revenue of $113bn. By mid-April, about 14,400 passenger planes around the world – 65% of the global fleet – had been placed into storage, according to the aviation research firm Cirium. Companies that have been brought to the brink, or in some cases collapsed entirely, include Virgin Australia and Virgin Atlantic, Flybe in the UK, South African Airways, LATAM and Avianca in South America, Compass and Trans States in the US. Airlines for America, a trade group, calculated that the last time the US averaged fewer than 100,000 daily passengers was in 1954. Emirates became so desperate for passengers that it promised to shell out $1,765 for a funeral if anyone died of Covid-19 after flying with them.

By June, Iata had to issue a revision: Revenues will fall by $419bn this year, precisely half of what airlines earned in 2019. These numbers are scarcely credible, even to industry veterans. Boet Kreiken, the executive vice-president for customer experience at the Dutch carrier KLM, recalled a meeting early in the pandemic, in KLM’s offices near Amsterdam’s Schiphol airport. His colleagues had brought in the latest figures for new bookings and the dismal projections for the summer ahead. “I’ve seen some crises in my time – the Iraq war, 9/11, Sars, the Icelandic volcano eruption,” Kreiken said. “I know in the gut what that feels like. But this was something else. I was staring at the chart and got so involved in thinking about the consequences that the others had to tell me twice: ‘Boet, start the meeting!’”

Prior to the pandemic, airlines had been wrestling with a different motivation against flying. Aviation accounts for 12% of all carbon dioxide emissions from transport, and flying is so cheap and easy that we can add unthinkingly to that gush of carbon in the seconds it takes to book a ticket on an app. London to New York and back creates 1,972kg of carbon dioxide – more than the average person in Madagascar or Colombia generates in a year.

Last year, KLM unveiled an initiative that sounded like a plea for less business. “Do you always need to meet face to face? Could you take the train instead?” a voiceover in an advert asked. “We all have to fly every now and then. But next time, think about flying responsibly.” (“There was a little bit of bravery in that,” a KLM executive told me. “It had to be pitched to the board three times before they approved it.”) The ad, bold as it was, also fit a broader pattern. As ever, individuals are being requested to tame their habits of consumption, even while governments and large corporations do far less than they might to curb their expenditure of carbon. At the same time, we’re assured by airline companies that our self-restraint has to be only temporary, and that some technological salvation – a plane running on batteries or hydrogen – will let us return to our habits very soon.

This year, as the industry’s fortunes tumbled, and as executives attempted to run their airlines even while most of their planes stayed on the ground, a different kind of technological salvationalism emerged. The future of flight now appears to be pinned on the discovery of a successful Covid-19 vaccine. The important problem of how much we ought to be flying gave way to the even more basic uncertainty of when and in what fashion we will ever fly regularly again at all.

KLM calls itself the world’s oldest commercial airline, by which it means it’s the oldest airline still operating under its original name. Last October, KLM turned 100, and Pieter Elbers, its CEO, was feeling cheerful. Elbers joined the airline in 1992, when he was 22, and worked all over the world before reaching the top in 2014. He told me that KLM’s profit margin for that year was a slender 2%. “From that, we moved to 8% last year, so there was a really positive, upbeat atmosphere.” By December 2019, he’d flown to so many KLM offices around the world to celebrate the centenary that he decided to spend New Year’s Eve at home in Amsterdam. A couple of weeks later, when KLM’s partner airlines in China began suspending operations, Elbers heard the first murmurs about a strange new virus.

Figuring that China would soon contain the disease, Elbers and his team cut down the frequency of KLM’s flights to China, reallocating those planes to US routes instead. By February, though, the pandemic had spread to Europe; by March, the Netherlands had locked down. At the KLM offices, only Elbers and half a dozen executives continued to come in to work, to wrestle with the crisis. Elbers left home at 6.30am every day and drove half an hour on vacant roads. “Everyone sat in my office, since it’s spacious enough to still be able to keep a good distance from each other.” Sometimes he would wander over to Schiphol and gaze at the slumbering planes and the desolate terminal.

The airline industry’s metabolism is ordinarily slow – planes ordered years in advance, routes plotted and pilots trained with measured care. During the pandemic, though, decisions had to be made with uncommon speed. Late in March, for instance, a KLM flight somewhere above Novosibirsk, bearing towards Shanghai, was told that every incoming flight crew now had to quarantine for 14 days in a Chinese state hospital. This rule was so new that it hadn’t existed when the plane left Amsterdam; circumstances had changed mid flight. Executives scrambled to get an approved exemption from Dutch and Chinese authorities so that the crew could stay aboard the plane in Shanghai and bring it home 18 hours later.

The same month, Elbers retired three Boeing 747s – huge, fuel-guzzling craft that were on the verge of being put out to pasture anyway. Mere weeks later, they had to be hastily pulled out of storage and pressed into service to ferry medical equipment and PPE from China to the Netherlands. There were complicated repatriation flights to be flown. Two thousand Dutch travellers had to be retrieved from Australia. The first repatriation flight to Sydney had to leave with 48 hours’ notice, but it had been 20 years since KLM had flown there – so long that the routes and permits had to be plotted afresh and reloaded into flight computers.

Usually, airline representatives convene at “slot conferences” twice a year, to divvy up landing and takeoff slots in airports around the world for the season ahead, said Vincent van Hooff, who oversees KLM’s flight operations. “We are not in the ad-hoc business. But now it was a totally new game. Would we still be flying to London tomorrow? Would we need more slots for repatriation flights? It was almost as if we had suddenly become a charter company.”

Amid this mayhem, the pandemic’s effects upon aviation seemed sudden and tectonic. Richard Aboulafia has an alternate view: “Nothing new is happening. It’s just happening faster.” Aboulafia is the vice-president of analysis at Teal Group, an aviation market research firm, and every month he sends out a chatty newsletter that is widely read in the industry. “Dear Fellow Dark Cloud Dwellers,” he wrote in May, peering ahead at the contours of a post-Covid industry. Airlines will hoard cash, he predicted. They will choose smaller, more efficient planes. They will fly more point-to-point routes, leaving behind the old hub-and-spoke networks – the kind that require us to fly from one town to another in a minimum of two legs, via a “hub” airport in a major metropolis. But these changes were under way even last year, he argued. The coronavirus has only made them seem more practical still.

One way to understand these trends, Aboulafia told me, is through the industry’s most beloved metric: the seat mile. If a plane with 300 available seats flies 1,000 miles, that flight clocks up 300,000 seat miles. Airlines are constantly comparing revenue per available seat mile, or Rasm, with cost per available seat mile, or Casm. Aboulafia, pronouncing these terms as “razzum” and “cazzum”, said: “As long as razzum is a nose above cazzum, you’re happy.”

In the 70s and the 80s, barring a couple of price spikes, aviation fuel – Jet A-1, as the industry calls it – was cheap. As a result, the industry’s ideas for keeping razzum above cazzum didn’t need to dwell too heavily on the cost of fuel. Instead, airlines pursued their beloved hub-and-spoke model – their elaborate networks that offered journeys only in multiple legs. To cultivate an airport as a hub, an airline booked out most of its landing and takeoff slots, so that it could corner the market on flights serving the surrounding area. After Delta developed the Atlanta airport as a hub, for instance, a customer found it more expensive to fly into the region on any other carrier.

In the hub-and-spoke model, passengers flowed thickly from one hub to another, before dispersing in thinner streams to their eventual destinations. To make these hub-to-hub flights, airlines ordered wide-body planes such as the 747, intending to stuff them with up to 500 passengers each. These planes consumed enormous quantities of fuel, and airlines then burned more still by shuttling their passengers from hubs to smaller airports. But the cost of Jet A-1 was so low that it almost didn’t matter. Besides, no matter which plane you flew, the takeoff phase always burned through Jet A-1 the quickest. The most fuel-efficient stage of flight came at cruising altitude, tens of thousands of feet in the air. It seemed to make sense, then, to put as many people as possible into a single takeoff and to then keep them up in the air for as long as possible. The hitch was, though, that airlines couldn’t always pack these massive aircraft to capacity, and they engaged in such ruinous price wars to fill their seats that Rasm suffered. A 2007 book by Adam Pilarski, once the chief economist for the aircraft manufacturer McDonnell-Douglas, carried the plaintive title Why Can’t We Make Money in Aviation?

Beginning in the 90s, and continuing well into this century, the price of fuel rose steadily, forcing airlines to re-examine their extravagance with Jet A-1. In 1989, a barrel of oil had cost $10, but in 2008, the price hit $147. In the uncertain years after 9/11, many airlines watched their passenger volumes flag, even as they kept having to pay for the new planes they had ordered years earlier. Ordinarily, airlines might have responded by raising ticket prices – except that, as the industry was fast deregulating everywhere, low-cost carriers emerged as fierce competition. These carriers shrank the cost of flying by doing away with frills such as meals and legroom. “That revolution was brutal,” Aboulafia said. “You couldn’t conduct business as usual.” The hub-and-spoke model appeared to be fading as well. Every city was building itself a decent airport, and people didn’t want to waste their time with layovers and connecting flights. Keeping Casm lower than Rasm needed a fresh approach.

Chief among these was to blow less money on Jet A-1. Airlines typically enhance their fuel efficiency by 1%-2% a year, and often these gains are won by tinkering around the edges: lighter seats, less water in the bathroom tanks. In 2017, when United Airlines reduced the weight of its paper in its inflight magazine, it saved nearly 770,000 litres of fuel a year – or $290,000 in costs. Aboulafia told me that, a decade or so ago, many airlines adopted power-washing, which reduces the drag on a plane by stripping it of greater quantities of oil, grime and bug corpses than an ordinary lather could ever do. Separately, several airlines started playing the futures market in fuel, to hedge against sharp price hikes. Delta bought a whole oil refinery near Philadelphia.

But the true leaps in efficiency were achieved by new craft, which airlines began to request from manufacturers in the early 00s. The Boeing 787, for example, claims to burn 20% less fuel than its older sibling, the 767. Van Hooff recalled how, when KLM inducted its first 787 into its fleet in 2015, a pilot accustomed to the 747 was appointed to fly it to Dubai. “The 747 is beautiful, but it burns around 11,000 kilos of fuel per hour on a trip like this, so he was used to seeing around 100,000 kilos on his storage gauge when he got into the cockpit,” Van Hooff said. “This time, he saw 50,000. He put in a call to dispatch to ask: ‘Are you really sure this is enough?’ Of course, he knew it was. But he couldn’t get past his gut feeling that he needed more fuel.”

Airlines put the 787 and other new planes on to point-to-point routes, slicing the hub out of the hub-and-spoke networks. More and more, Aboulafia said, carriers are buying smaller, single-aisle planes for these direct flights, and shedding their old, large craft. Even before the pandemic, Emirates had already decided not to buy any more Airbus A380s, a plane that costs $500m and can carry up to 868 people – a plane so big that airports have to redo their tarmac and their gates to accommodate it. In July, British Airways decided to retire the 31 Boeing 747s left in its fleet.

Tickets stayed cheap, though, and not just because of the competition from low-cost airlines. Peter Morris, who was once Iata’s chief economist, told me that back in 1995, 25% of the cost of a ticket actually went into producing and selling it: courting travel agents, paying out commissions, printing tickets securely. The internet did away with that, replacing it with attritional algorithm battles. Automated web crawlers alert an airline many times a day if a rival drops its price on a route, so that analysts can decide if their airline can afford to do the same. Boet Kreiken, who once worked for the Dutch Air Force, called the price game “mutually assured destruction”. This is among the reasons, people in the industry kept claiming, that airlines hardly make any money.

Morris has no time for these “weepy stories with violin accompaniment that airlines tell”. “The truth is, over the last few years, the airline industry has never been so profitable.” Carriers have pruned their expenses so much, and convinced so many people to fly so often that, despite low prices, Rasm has steadily surpassed Casm. As of last December, the global airline industry had been in the black for 11 straight years.

Cheap ticket prices, in fact, are central to an illusion fostered by the airline industry over the past 20 years. The illusion is that the money we pay for a ticket covers the cost of flight in a deeper sense – the cost of transporting us through the air, but also the cost exacted from the environment – and that the booking of a £42 return flight for a stag weekend in Bratislava isn’t worth more than a casual thought. The irony about KLM’s advertisement last year to “Fly Responsibly” is that it came after years of the industry exhorting us to fly irresponsibly. “Do you always need to meet face to face?” the ad chided us gently, as if airlines hadn’t worked to plant in us the belief that face time – to pitch a client, or to lunch with colleagues – was both optimum and trivially inexpensive. Then the coronavirus arrived, the prospect of face-to-face meetings evaporated, and for the first time in decades, flying became a luxury once again.

In the depths of the flying freeze, in late April, 166 of KLM’s 204 planes were grounded. Instead of taking them to boneyards, KLM decided to keep them all at Schiphol – pulled up to the departure gates, or parked wing-to-wing in a zigzag pattern on one runway, after steel plates had been laid down so that the combined weight of the aircraft didn’t damage the tarmac. Airplane storage is a funny, delicate affair. The saying “time is money” is so emphatically true in aviation that even planes in long-term storage must be kept as close to airworthy as possible, so that they can bolt into the air to continue earning back their massive price tags.

On a video call one August morning, Ton Dortmans, KLM’s head of engineering and maintenance, explained what his team had to do to bed their planes down through the spring and summer. Fuel tanks were emptied, although not entirely: “You still need some weight in the plane, for the bursting wind we get here in Amsterdam.” For the same reason, the blades of the engine fans were locked into place with straps, so that, on gusty days, they didn’t whirl around endlessly and wear their parts out. The water tanks were drained. Engineers 3D-printed covers to place over the small holes on the plane’s surface, which conceal sensors that measure air pressure and altitude. The covers protected them from moisture and insects.

Every seven days, someone would climb into the plane and run the engines for 15 minutes to keep them functional. The air conditioning was switched on to keep the humidity at bay. “And the tyres – well, it’s the same as a car. If you keep a car parked for more than a month, you get flat tires,” Dortmans said. So a tug pulled the plane forward and back every month, to keep the wheels and axles in shape. Still, there were some surprises. In the absence of the roar of jets, birds began to appear around Schiphol again, and one day, a ground engineer told Dortmans that he’d found a bird starting to nest in a cavity in the auxiliary power unit. “I’m hearing all these birds and now I find this,” he told Dortmans. “It feels like I’m out in the woods.”

Pilots couldn’t be put away in storage in quite the same way. KLM has 3,000 of them, all of whom must fly a minimum number of hours and perform three takeoffs and three landings every 90 days to stay “current” – to still be allowed to pilot a plane. During the lockdown, the pilots on the ground had to retain their currency by rotating through KLM’s nine simulators. From the outside, these simulators look like motorcycle helmets for giants, and a pilot, having climbed into one and closed the hatch, can be put through a pretty immersive rehearsal for flight. The summer slipped by. At some point, a number of pilots had spent six months without going up. Van Hooff resolved that whenever they flew next, they had to do so alongside a trained flight instructor.

Flying was its own challenge, because all manner of routine vanished. Week to week, pilots saw their routes and aircraft change, and they touched down into an ever-shifting matrix of rules and norms. US regulations were so inconsistent – which states demanded masks, which states permitted crew members to leave the hotel, which states required them to keep to their rooms – that van Hooff put a team to work just to update these restrictions multiple times a day, and to feed the information up to the planes vaulting over the Atlantic. A source at another European airline, who asked to remain anonymous, told me that after one flight to New York at the peak of its cycle of infection, the plane’s crew felt uncomfortable heading to a city hotel for the night. Instead, they slept in the business-class cabin.

A tide of cancellations rolled in. Passenger numbers dropped by 95%, from 9 million in the first quarter of the year to 500,000 in the second. To field complaints and to issue vouchers and consolations, KLM put 800 of its employees on temporary customer-care duties, which they performed from their bedrooms or living rooms. In Manila and in Santiago, call centres were vacated during lockdowns. The staff took their computers home and responded to calls from there. “It was double trouble, triple trouble,” Boet Kreiken, the customer-experience chief at KLM, said.

Late in July, Elbers announced that KLM had lost a record €800m in the first half of the year. The airline received a bailout from the Dutch state: €1bn in direct loans, and another €2.4bn in bank loans guaranteed by the government, all with firm strings attached. Costs had to be cut; new environmental conditions had to be met; the airline had to be restructured. Elbers sent around a note to his employees, in which he admitted that these conditions were “difficult” and “raw”.

By the end of the summer, the KLM group had announced 4,500-5,000 upcoming job cuts, out of its staff of 33,000 – a combination of layoffs, voluntary retirements, and terminations of temporary contracts. The scenario recurred across the industry. American Airlines plans to slash 40,000 jobs from its workforce. British Airways: 12,000 jobs. Qantas: 6,000. Ryanair: 3,250. The industry will incur losses of $84.3bn this year, Iata estimates – and that’s if there’s no fresh spurt of disease. “It’s going to be a marathon, not a sprint,” Elbers keeps warning his colleagues. In his July note to his staff, he offered just one word as KLM’s primary priority: “Survive.”

As yet, there has been no comprehensive reckoning of how many tonnes of aviation emissions the pandemic has averted – in part, of course, because the pandemic is still around, and many planes are still grounded. One rough analysis found that the cancellation of 1m flights in March wiped out the equivalent of a month of the UK’s carbon dioxide emissions. In March, I met Andreas Schäfer, a professor of energy and transport at University College London’s Energy Institute. Schäfer thinks about aviation and emissions all day long, and had been planning on giving me a lot of data, but his laptop was lethargic that afternoon. He would make an observation and then have to talk around it, marking time while a PowerPoint or a pdf loaded and supplied him with the necessary numbers.

Between 1980 and 2015, Schäfer said, aviation emissions increased by 2.2% annually. This isn’t surprising, he noted, because the boosts in fuel efficiency in recent years notwithstanding, there are just more people flying. How many more? He summoned another document and, five minutes later, said: “Ah, here we go!” In those same 35 years, even as planes were using 2% or 3% less fuel every year, the demand for air transportation grew by 5.4% annually. In that difference lies aviation’s contribution to the climate crisis.

“Not only airlines, but even plane manufacturers are nervous about the CO2 issue, and about people’s perception of them,” Schäfer said. In 2013, the International Civil Aviation Organization (ICAO), the United Nations body that lays down standards for airlines, set new requirements for fuel efficiency and carbon emissions. Three years later, the ICAO adopted the Carbon Offsetting and Reduction Scheme for International Aviation. Corsia, as it’s known, aims to reduce international aviation emissions to half their 2005 levels. Airlines also pledged to purchase carbon offsets to atone for any excess growth in emissions beyond 2020.

The incremental rewards of a better engine or a leaner seat will not get airlines to these targets, and they know this. Esmée van Veen, a sustainability manager at KLM, said that the airline had begun a climate action plan in 2008 that relies upon fuel efficiency, biofuels and a voluntary carbon-offset programme, which funnels passengers’ offset payments into a reforestation project in Panama. “We’ve stabilised our carbon emissions, and now we’re ready to decrease it,” she said. In 2011, KLM flew its first commercial flight with biokerosene, made from used cooking oil, added into its fuel mix. “It isn’t much. Right now, it’s about 0.2% of all the fuel we use,” she admitted.

Van Veen can outline stages of progress that might eventually turn flying into a zero-carbon enterprise, but she’s careful to note that this is an extrapolation – that it depends on new technologies bearing fruit. By 2030, KLM’s planes taking off from the Netherlands will use a fuel mix that’s 14% biofuel and “synthetic” kerosene, reducing both the need to drill for fresh oil and the emissions that the oil industry spews in the process. Synthetic kerosene – fuel concocted in a refinery – is expected to be made partly from carbon dioxide drawn out of the air, so its overall emissions will be up to 80% less than those from Jet A-1, Van Veen said. Over shorter distances, some planes might be hybrids, powered by batteries as well as fuel. And subsequently, by the middle of the next decade, she said, “we expect there will be a hydrogen-propelled aircraft launched in Europe”. The hydrogen plane is the industry’s recurrent dream, its equivalent of cold fusion or the driverless car.

But I also spoke to several people who were sceptical, both of Corsia and of all this nascent green tech. Schäfer thinks Corsia’s targets are timid – that they’ve been set in a way that won’t pinch the industry much. Corsia’s spine is a carbon-offset programme, and offsets are cheap. Brandon Graver, a researcher at the International Council on Clean Transportation, has seen that most of the money from offsets goes into administrative costs, not into actual projects. It’s even doubtful if these projects result in a permanent reduction of carbon, he said. “You hear, ‘Tree planting, tree planting, tree planting’, but only a certain percentage of these trees end up living past a year.” He called offsets “modern-day indulgences”. We pay for our sins to be forgiven, but also for the licence to sin again.

The trouble is that the technologies that might usher us into an age of cleaner flight aren’t at hand yet. The volume of biofuel and other alternatives being manufactured is vanishingly small. Graver’s team calculated in 2017 that all the world’s supply would keep the world’s planes in the air for a total of 10 minutes. (Environmental experts worry that biofuels, made out of products such as palm oil, will do more damage than they promise to repair.) If synthetic fuel becomes viable, it will cost more than $3 a gallon at first, Schäfer told me. “Oil is now around $1 a gallon. So why would airlines buy the synthetic stuff?” The battery that’s both small and powerful enough to take a plane across the Atlantic, or from Paris to Perth, is not even on the horizon. In the near term – a timescale that matters enormously to climate change – the only way to decarbonise aviation is to fly less. As an option, that seemed plumb absurd until this year, when we were forced to learn how to live without planes.

In the coming years, airlines will be wrenched in two different directions. Their revenues will stay low and wobbly; Iata predicts that passenger numbers will return to pre-pandemic levels only by 2023, but others in the industry grimly cite 2024 or 2025. Simultaneously, many carriers will have to invest in climate change plans, buying offsets or funding research. Already, they’ve had to convince the ICAO to relax some Corsia obligations. In Europe, governments have imposed environmental reforms among the terms for airline bailouts. In return for €15bn, for instance, Air France has committed to halving domestic flight emissions by 2024 and to restricting short-haul flights where trains run instead.

In the US, too, the government organised a $25bn aviation bailout, even though the four biggest airlines blew through nearly $40bn in cash over the last five years simply to buy back shares and prop up their stock prices. Here, there were no climate change riders. “Sustainability in the US is marginally more important than keeping enough toner in the fax machine,” Aboulafia told me.

But airlines need passengers if they are to repay bailout loans, or mop up their emissions. In both the US and Europe, where growth was already slowing, the prompt and full return of customers isn’t at all a sure thing. This is especially true of business flyers. “Covid gives companies a reason to rethink travel expenses,” said Jeff Pelletier, who runs Airline Data, an analysis firm based in Houston. Business travellers make up 12%-15% of a plane’s passengers, but they sit up front, so they contribute as much as 75% of a flight’s profits on some routes. “Not every company will cut back,” Pelletier said. “But some will. They’ll figure they’d rather spend a couple of bucks on a Zoom meeting instead.”

In Asian countries including China and India – markets that have been growing faster than most others, as flights became increasingly affordable – Dennis Lau expects a quicker rebound. Lau, a Hong Kong-based analyst at Cirium, told me that “climate change is not a part of the industry’s conversation here”. Corsia is, for many governments in the region, one more instance of western nations promoting environmental standards that they have violated for decades, and that will curb the economic development of Asian countries. China, India and Russia have agreed to participate in Corsia only from 2027 onwards. And there’s still considerable doubt about how thoroughly Corsia can be enforced, Lau said. “What will you do if countries just refuse to report their emissions?”

During my reporting, I kept being told that eventually the pandemic’s effects would fade – that the world’s economy, having been opened wide by affordable flights, couldn’t be zipped shut again, and that people will get back on planes the second they believe it’s safe to fly again. But in the interim, a period of consolidation is in the offing. More airlines might go out of business, and others will be bought by bigger carriers. Airlines will have smaller fleets, Aboulafia wrote in a newsletter. More planes will be smaller, single-aisle jets flying point to point, because while the coronavirus still lurks, no one wants to spend a longer time than necessary in connecting flights or layover airports. Flying will feel both more austere, in these aseptic and functional flights, and more luxurious, since there will be less of it.

In June, KLM’s engineers started to rouse some planes out of their hibernation. They replaced leaking toilet taps, fixed faulty rubber rings and tested the emergency lights. “The second-last thing we do is to check the fire extinguishing systems and the flight controls,” Ton Dortmans, KLM’s engineering chief, told me. “And then the last thing is: we run the engines and put all the systems on again to see if they work – air conditioning, navigation, all of it.” For a brief spell of time, uninhibited travel looked possible again, but then fresh bouts of disease appeared all over the continent. The week I was scheduled to visit KLM in Amsterdam, in mid-August, the UK government announced self-isolation rules for any traveller returning from the Netherlands, so my trip fell through. “You should have been here, to see what we were doing,” Dortmans lamented on our video call.

He had been coming up with a fallback scenario for the winter. “It’s a question we have to answer now. If it’s a snowy, hard winter, maybe we have to rethink how our planes are parked here. You have to think about the water and the fuel in the planes, and how they react to freezing temperatures.” If his planes had to be parked for more than 180 days through the winter, Dortmans said, he would think about sending some away. Perhaps to Teruel, or perhaps to the boneyard in California’s Mojave desert, where they will be warmer and drier, and where they can wait to find out if they will be needed again.

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