A landing slot, takeoff slot, or airport slot is a permission granted by the owner of an airport designated which allows the grantee to schedule a landing or departure at that airport during a specific time period.
While it’s kept mostly hush-hush, a leaked document revealed Oman Air set a record by paying £58 million for a pair of take-off and landing slots at Heathrow in early 2016. The Gulf carrier is understood to have bought the pair, which includes a highly prized early morning arrival, from Air France-KLM.
A year later, Scandinavian Airlines made news when it revealed that it sold two slot pairs at Heathrow for almost £60 million.
Pre-pandemic, European and airports instituted an 80/20 policy. That is; the airline allocated a slot must fly at least 80% of the allocated slots over a year. If you’re interested in the full details of the policy, here’s the full text of the EU Slot Regulation EEC 95/93.
There is good reason for this. It ensures the aviation market remains competitive and airlines are incentivised to trade or hand back unused slots so that other airlines can fly them instead, including new market entrants.
However, along came COVID-19 and an almost blanket ban on international travel. The 80:20 rules were suspended for six months in March 2020 to stop airlines running empty flights to hold on to their landing rights. This was extended for another six months in September 2020.
More recently, the UK government is operating a 70% rule throughout the summer of 2020, expecting passenger volumes to be somewhere similar to pre-pandemic levels.
So now these restrictions are back in place, at least in the UK, I wanted to take a look at the impact of so-called ghost flights over the past 2 years.
Methodology
“Empty or almost empty” has been classified as flights with a load factor of 10% or less for this question. This means that the number of terminal passengers on the flight was no more than 10% of the number of available seats. Scheduled and chartered flights are included, as are flights to Oil Rigs.
Results
Count of passenger flights operating from UK airports with load factor less than 10%
You can see in March 2020, for most of which the 80:20 rules was in place, the number of ghost flights (1772) was at it highest during the pandemic, as airlines couldn’t fly passengers but were tied to the 80:20 rule before it was paused.
As travel started again in the Autumn of 2020, you can see the total number of ghost flights increasing again (1544 in September 2022, the second highest month for ghost flights). The assumption here is passengers simply didn’t want to travel but airlines ramped up the number of flights, thus load volumes were below 10% on operating flights.
In total there were 14,472 ghost flights over the period of Mar 2020 and Sept 2021.
Total ghost flights by airport Mar 20 – Sept 21
| Reporting Airport | Total (Mar 20 – Sept 21) |
|---|---|
| Kirkwall | 0 |
| Dundee | 3 |
| Exeter | 10 |
| … | … |
| Gatwick | 1044 |
| Manchester | 1548 |
| Heathrow | 4910 |
Kirkwall had no ghost flights, whereas Heathrow had 4910 over the period Mar 20 – Sept 21.
Though Kirkwall handled 14,247 flights in 2019. Heathrow handled 80,886,589.
Ghost flights Sept 20 – Sept 21 as % of normal flight volume (2019 (top 20 UK airports)
Looking at the top 20 airports, Aberdeen has the largest percentage (0.019%) of ghost flights (Sept ’20 – ’21) versus 2019 (pre pandemic) total aircraft movements. One reason for this might be due to the types of flights. In the dataset I am using
Scheduled and chartered flights are included, as are flights to Oil Rigs.
Aberdeen serves oil rigs in the North Sea, and is therefore likely to operate transfers for workers which might usually have a load factor of less than 10%, even pre-pandemic.
Bristol (0.0047%) and Liverpool (John Lennon) (0.0046%) are the second and third respectively when it comes to worst offenders for total ghost flights as a percentage of normal operation.
Ghost flights estimated c02 emissions
Let’s assume a ghost flight operates on the same averages I used for my post on aircraft emissions for delegates travelling to last years COP 26 summit;
On average, passenger aviation emitted 90 grams of CO2 per passenger-kilometer in 2019
International Council on Clean Transportation
Ghost flights also fly planned routes (to ensure slots are kept at both airports). So let’s also assume the average flight distance used for calculations in the COP 26 post too; 3000 km (6000 km for both legs).
Note, we’re assuming the average flight lengths to be identical across airports. In my calculation the major international airports cause the most emissions from ghost flights simply because the ran more of them.
The reality is that emissions will be much higher from these airports. This is because departing and arriving flights tend to fly much longer distances when compared to regional airports (where real emissions will likely be lower than my calculation for the same reason).
In total, I’ve estimated total emissions from ghost flights between March 2020 – Sept 2021 from listed UK airports was 7152.84 tons of CO2.
Ghost flights cost to the airline
Current jet fuel costs about $0.95 / litre.
According to this Wikipedia article, jet fuel weighs 0.81 kg/l.
A Boeing 787-9 burns 5.77 kg of fuel per km.
Therefore, per km, a 787-9 burns $6.77 worth of fuel per km ((5.77/0.81)*0.95).
Operating an airline is not cheap!
Assuming the average ghost flight flew 6000 kms, and the airline paid current costs $0.95/litre (total $40,620 per flight), airlines flying ghost flights out of Heathrow paid almost $200 million in fuel costs to operate these empty or almost empty flights.
In total I estimate over half a billion dollars ($538,052,520) was spent by airlines operating ghost flights from these UK airports during the pandemic.
Improvements
This post only considers UK airports. Ghost flights are not unique to the UK. As noted previously, the 80:20 rules applies to US and EU airports too. Lufthansa has apparently operated over 18,000 ghost flights — if true, 4,000 more than all UK airport ghost flights combined.
It would therefore be a logical next step to compare ghost flights worldwide, and by airline (whilst also factoring in the improvements to my calculations as noted throughout this post).
tl;dr
I estimate over half a billion dollars ($538,052,520) was spent by airlines operating ghost flights from UK airports during the pandemic resulting in a total of 7152.84 tons of CO2 emissions.