A commercial aircraft flies over the Yas Viceroy Abu Dhabi Hotel in the port at the Yas Marina circuit in Abu Dhabi on November 26, 2015 ahead of the Abu Dhabi Formula One Grand Prix.  (Photo by Tom Gandolfini/AFP/Getty Images)

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In the early days of the pandemic, when demand for air travel abruptly flatlined and international borders closed, “ghost flights” became a common phenomenon.

These were empty or near-empty planes traversing the skyline as airline schedules kept to their contractual obligations to fly. The problem is that, more than two years on, they’re still haunting the skies above us.

A new report by the Guardian, based on a freedom of information request, found that at the end of last year there were around 500 “ghost flights” departing from the UK per month.

And in January 2022, analysis from Greenpeace claimed that more than 100,000 “ghost flights” would sail over European skies this winter. The climate damage, claims the environmental group, is “equivalent to the yearly emissions of more than 1.4 million cars.”

The Greenpeace figures were extrapolated from a December interview with Lufthansa CEO Carsten Spohr in which he warned that Lufthansa Group was facing the prospect of 18,000 superfluous flights over the six-month winter season to retain its slots under European rules.

On the basis that Lufthansa’s air traffic accounts for 17% of the European market, Greenpeace reckons the total number of Europe’s ghost flights would generate 2.1 million tonnes of CO2.

The analysis has triggered a torrent of outrage. Campaigner Greta Thunberg asserted that “Brussels Airlines [part of the Lufthansa group] makes 3,000 unnecessary flights to maintain airport slots.” In the UK, a petition was launched, appealing to the government to ground unoccupied flights.

Lufthansa, meanwhile, says it’s doing its best to fill all its aircraft, but was struggling to balance Covid chaos with the need to hold onto its slots.

“Unnecessary flights are not empty or ‘ghost’ flights,” a spokesman for the airline told CNN. “They are scheduled flights that are poorly booked due to the pandemic. Despite poor demand, Lufthansa Group Airlines must operate these flights to continue securing takeoff and landing rights at hubs and major EU airports.”

Lufthansa says that the emergence of the Omicron variant is the reason its projections for the season ahead were so far short of the reality. The crisis “led to significantly increased travel restrictions and cases of illness in the general population and among employees,” says its spokesperson. “This unexpectedly not only reduced the prior trend of recovery, but also triggered a significant slump in demand.”

Last October, the aviation industry pledged at the International Air Transport Association (IATA) annual meeting to achieve net-zero carbon emissions by 2050.

Numerous players – including hub-based carriers, low-cost airlines, regulators and environmental lobbyists – are at loggerheads in a multi-way blame game over the absurd wastefulness of unnecessary flights.

“We’re in a climate crisis, and the transport sector has the fastest-growing emissions in the EU – pointless, polluting ‘ghost flights’ are just the tip of the iceberg,” says Herwig Schuster, spokesperson for Greenpeace’s “European Mobility For All” campaign.

“It would be irresponsible of the EU to not take the low-hanging fruit of ending ghost flights and banning short-haul flights where there’s a reasonable train connection,” he adds.

So why on Earth are these Mary Celeste flights still ongoing – and what are aviation’s stakeholders doing to disentangle themselves from the red tape that has ensnared the airlines into this climate-damaging mess?

Precious assets

The reason airlines continue to operate these expensive flights is because the industry is engaged in a slots game more high stakes and lucrative than anything you’ll find in Las Vegas.

Even when passengers are staying away, airlines still need to protect their slots: their scheduled time on valuable routes.

Slots are extremely precious assets for airlines. With more than 200 of the planet’s busiest hubs operating at full capacity, demand for flights exceeds the availability of runways and space inside the terminals.

To manage this, capacity at congested airports is segmented into slots. These are the facility to land, disembark passengers, refuel, take on a new cohort of passengers and then take off again – all within a specified and regulated time frame.

Carriers then plan their schedules based on slot availability at both ends of the route. To maximize revenue, the schedules have to align with demand – early morning slots for business travelers traveling short-haul, same-day-return trips are highly prized.

But synchronizing the timing of both ends of the journey when the most desirable airports are full up is no easy feat.

“If you take off from one place you need to know you can land at a certain time at another,” says Paul Steele of the IATA. “If you tinker with slot allocation at one end of the process, it creates chaos at the other end, and therefore we need a harmonized system.”

That’s where the Worldwide Airport Slot Guidelines (WASG) come in. These are the foundation upon which the global slot allocation process works. The Guidelines (jointly published by IATA, Airports Council International and the Worldwide Airport Coordinators Group) aspire to deliver “transparency, flexibility, certainty, consistency and sustainability … for the benefit of airlines, airports and consumers.”

Lufthansa's boss says the group will have to run 18,000 unnnecessary flights over the winter season in order to hold onto its airport slots.

Mind-boggling system

But with airlines operating hundreds of city-pair routes – some synchronized with connecting flights – this is a mind-boggling system to administer, and the allocation must be done twice a year for the summer and winter season schedules.

To re-plan all of this every six months would be too complicated, so there’s a rule that states that if an airline successfully uses its slot at least 80% of the time, it is allowed to retain the slot the following season, a system known as “grandfather rights.”

There’s therefore very little flexibility in the network for introducing new routes, especially at congested airports. And that’s why slots are gold dust.

In the UK, Heathrow Airport holds the most valuable slots. Limited capacity there has propelled the price of slots skywards, with an early morning slot pair worth around $19 million, falling to $13 million at midday and $6 million in the evening, according to a UK House of Commons briefing paper.

Record-breaking deals where airlines have traded these slots include the case of Oman Air, which was reported to have paid $75 million for a pair of takeoff and landing slots at Heathrow in early 2016. In March 2017, SAS Scandinavian Airlines sold two slot pairs at Heathrow to American Airlines for $75 million, according to the same paper. Usually, however, airlines keep these contractual details under wraps.

Slots can also be traded in other ways, such as swaps between carriers, similar to the way that football teams have players out on loan.

Because of the “grandfather rights” system, airlines reducing their use of the slots risk losing them. Cutting capacity is threatening the airlines’ hold on their slots, which is why planes might still be operated even when hardly anyone is flying in them.

Loosening the red tape

Two years ago, when the initial impact of Covid decimated the airline networks, the 80% rule was relaxed.

In the United States, the US Federal Aviation Administration (FAA) waived the slot usage, just as it had previously suspended the regulation in 2002, 2003 and 2009 – following the September 11, 2001 terrorist attacks in the United States; the outbreak of SARS; and the global financial crisis, respectively.

And in Europe, for the current Winter 2021-2022 period, the “use it or lose it” threshold was lowered to 50%. But airlines are facing increased uncertainty and want greater latitude for retaining their slots.

Air France-KLM Group, for example, issued a statement, seeking “the current [Covid] situation to be better taken into account in the application of European regulations so that airlines can continue to adjust their offer to actual demand levels.”

In particular, the Group seeks increased flexibility “in the application of the force majeure rules allowing for derogations from the 50% slot utilization rule.”

In response, and perhaps in recognition that the Omicron variant is now playing havoc with everybody’s travel plans, the European Commission issued an extension to the slot relief rules effective until October 29, 2022. However the Commission is raising its threshold to 64% in April.

“The progress in vaccination campaigns and the EU Digital Covid-19 Certificate have helped to restore traveler confidence and air connectivity in the EU, putting the industry in a stronger position to deal with short-term shocks,” explains Adina Vălean, the EU’s commissioner for transport. “Even if we are not there yet, we can take a step further towards the return to normal airport slot management next summer.”

Vălean says the EU is monitoring the situation, acknowledging the lingering impact of Omicron on airline bookings. “The Commission has demonstrated throughout the Covid-19 crisis its willingness and ability to act swiftly where needed, and this will remain the case in the coming months,” she adds.

Heathrow is the UK's busiest airport.

Payback time?

From the perspective of one of Europe’s largest low-cost carriers, solving the problem of ghost flights may be straightforward.

Ryanair boss Michael O’Leary says that, “If Lufthansa really needs to operate these flights (solely to prevent the release of these slots to competitor airlines), then they should be required to sell these seats to the public at low fares.”

O’Leary’s contention is that Lufthansa and its subsidiary airlines (Brussels Airlines, Swiss and Austrian) have benefited from billions of State Aid. Consequently, “instead of operating empty flights just so they can block slots, Lufthansa should release the seats on these flights for sale at low fares to reward the German and European taxpayers who have subsidized it with €billions during the Covid crisis,” he says.

However, Lufthansa’s spokesperson argues that it’s a different situation for larger airlines. “Network companies like Lufthansa Group are more dependent on slots for feeder flights that connect passengers to long-haul routes at group hubs than low-cost airlines that tend to fly to smaller airports where there usually is no shortage of slots,” he says.

The only exception to the use-it-or-lose-it rule is the force majeure clause. However, this is not interpreted uniformly throughout Europe. Many countries grant no exceptions or only a few.

Instigating exceptions is also very bureaucratic and time-consuming. Each exception must be granted individually: for the starting point and the destination – therefore two approvals are always required. Since approvals are usually granted on short notice before a flight, there is no longer enough time for passengers to be rebooked.

Lufthansa says it wants all EU member states to be granted exceptions to takeoff and landing rules so that the issue can be addressed flexibly, minimizing bureaucracy for the current winter schedule. “The EU Commission should advocate uniform regulations so unnecessary flights are avoided and airlines are able to better plan,” says its spokesperson.

Protect and compete

Meanwhile, ACI Europe, the professional association of airport operators which represents over 500 airports in 55 countries, has expressed dismay at the escalating industry and political rhetoric around ghost flights. It’s also casting doubt on the reasoning of the major hub carriers that ghost flights are unavoidable.

“A few airlines are claiming they are forced to run high volumes of empty flights in order to retain airport slot usage rights. There is absolutely no reason why this should be the reality,” says ACI Europe director general, Olivier Jankovec.

Slot usage rules, he says, need to achieve two things in the current circumstances: “to protect airlines from the worst of unpredictabilities which are out of all our hands, and crucially, to also ensure that airport capacity is still used in a pro-competitive way.”

Jankovec adds that reconciling commercial viability alongside the need to retain essential connectivity and protect against anti-competitive consequences is a delicate task: “We believe that the European Commission has got this right. Talk of ghost flights, and of their environmental impacts, seems to hint at a doomsday scenario which has no place in reality. Let’s stick to the vital task of recovering and rebuilding together”.

And going one step further, on February 2, IATA released a statement welcoming updated guidance from the European Airport Coordinators Association, intended to provide a more harmonized policies on slot-use thresholds.

Willie Walsh, IATA’s director general, said such a move was crucial for “sustaining critical European air connectivity” and for “leveling the playing field with jurisdictions that have recognized the need for full flexibility.”

That promise of flexibility will be pivotal to the minimization of empty flights. But ultimately, their complete eradication will only be achieved when the public’s propensity for air travel, facilitated by the eventual and complete conquest over the Covid virus, enables airlines to fill their planes with fare-paying passengers – instead of ghosts.

Top image: A plane flies over the Yas Viceroy Abu Dhabi Hotel in Abu Dhabi in November 2015. (Photo by Tom Gandolfini/AFP/Getty Images)

Paul Sillers is an aviation journalist specializing in passenger experience and future air travel tech. Follow him at @paulsillers