Airport slot

A landing slot, takeoff slot, or airport slot is a permission granted by the owner of an airport designated as Level 3 (Coordinated Airport), which allows the grantee to schedule a landing or departure at that airport during a specific time period.^[1] Slots may be administered by the operator of the airport or by a government aviation regulator such as the U.S. Federal Aviation Administration.^[2]

Landing slots are allocated in accordance with guidelines set down by the International Air Transport Association (IATA) Worldwide Airport Slots Group. All airports worldwide are categorized as either Level 1 (Non-Coordinated Airport), Level 2 (Schedules Facilitated Airport), or Level 3 (Coordinated Airport). At Level 2 airports, the principles governing slot allocation are less stringent; airlines periodically submit proposed schedules to the administrating authority, rather than historic performance. Participation is not mandatory, but reduces congestion and non-participants are penalized if the airport must later be designated level 3.^[2]

As of summer 2017, a total of 123 airports in the world are Level 2 airports, and 177 are Level 3 airports.^[3]

Allocated landing slots may have a commercial value and can be traded between airlines. Continental Airlines paid US$209 million for four pairs of landing slots from GB Airways at London Heathrow Airport, $52.3m each.^[4] The highest price paid for a pair of take-off and landing slots at Heathrow Airport was $75m, paid by Oman Air to Air France–KLM for a prized early morning arrival, reported in February 2016. A year before, American Airlines paid $60m to Scandinavian Airlines.^[5]

Heathrow slot valuations^[6]
Year	Buyer	Seller	daily slot pairs	transaction (£M)	slot value (£M)
1998	BA	Air UK	4	15.6	3.9
2002	BA	BA Connect	5	13	2.6
2002	BA	SN Brussels	7	27.5	3.9
2003	BA	SWISS	8	22.5	2.8
2003	BA	United	2	12	6
2004	Virgin	Flybe	4	20	5
2004	Qantas	Flybe	2	20	10
2006	BA	BWIA	1	5	5
2007	BA	Malev	2	7	3.5
2007	BA	BA	7.3	30	4.1
2007	Virgin	Air Jamaica	1	5.1	5.1
2007	BMI		77.7	770	9.9
2007	unknown	Alitalia	3	67	22.3
2008	Continental	GB Airways/Alitalia/Air France	4	104.5	26.1
2013	Delta	unknown	2	30.8	15.4
2013	Etihad	Jet	3	46.2	15.4

As supply is limited, slot trading became the main solution to enter Heathrow and transfers grew from 42 in 2000 to 526 in 2012 and over 10 years the average priced slot was equivalent to £4 per passenger.^[7]

If an airline does not use an allocation of slots (typically 80% usage over six months), it can lose the rights. Airlines may operate ghost or empty flights to preserve slot allocations.^[8] To avoid pollution and financial losses caused by an excessive number of empty flights, these rules have occasionally been waived during periods of temporary but widespread travel disruption, including after the September 11, 2001 attacks, and during the SARS epidemic, the Great Recession, and the COVID-19 pandemic.^[9]