What Are Slot Restrictions?

How it works

At most airports an aircraft can arrive or depart whenever traffic control allows. At a small number of the busiest airports, runway and terminal capacity is limited enough that every take-off and landing must be pre-allocated a specific time, called a slot, before the flight is scheduled. This is a separate system from a noise curfew, which restricts hours of operation rather than allocating specific times within them; a slot-controlled airport can also have a curfew, but the two rules do different jobs.

In the United States, the FAA designates certain airports as slot-controlled under 14 CFR Part 93. John F. Kennedy International, LaGuardia and Ronald Reagan Washington National are the best-known examples, the latter governed by Part 93's dedicated high-density provisions for that airport. A charter or private operator flying into one of these airports typically obtains a reservation through the FAA's Air Traffic Control System Command Center, usually arranged by the operator or its ground handler rather than the passenger directly.

In the UK, airports such as London Heathrow, London Gatwick and London City are classified as fully coordinated ("Level 3") airports. Slots there are allocated by Airport Coordination Limited, the UK's independent slot coordinator, operating under the retained version of EU Regulation 95/93 as it applies in UK domestic law following Brexit. In the EU, the same underlying instrument, EU Regulation 95/93 as amended, applies at Level 3 airports such as Paris Charles de Gaulle, Frankfurt and Milan Linate, with each member state designating its own national coordinator.

For a charter client, the practical effect is that the airport, not the operator, sets the available windows for arrival or departure at these locations. The broker or operator requests a slot on the client's behalf; if the preferred time is unavailable, the alternatives are usually a different time at the same airport or a different, uncoordinated airport nearby. This position is described as it stood on 28 September 2026; slot rules and airport designations change periodically and should be checked against the current regulation.

Cost impact

Slot restrictions carry no direct regulatory fee in the United States, the UK or the EU; a slot itself is not sold to a charter client. The cost shows up indirectly, through what happens when the preferred slot is unavailable. Requesting or amending a slot is often handled by a ground handler or FBO, which may charge an administrative fee for the coordination work; that fee is set by the handler, not the regulator, and varies by airport and provider. Where no slot exists near the preferred time, the practical alternative is often a nearby airport that is not slot-controlled, which shifts part of the journey onto a ground transfer, or forces a positioning leg that would not otherwise have been needed. Suppose, for illustration, a preferred slot at a Level 3 coordinated UK airport is unavailable, and the operator instead lands at an airport 40 kilometres away: an illustrative £600 ground transfer, or an illustrative £2,000 positioning leg to bring the aircraft back afterwards, is added to a bill that a successful slot would have avoided. The size of the effect depends entirely on which alternative the operator and client choose, so it is best read as a range rather than a fixed charge.

Example

Suppose, for illustration, a charter client wants to land at London City Airport, a Level 3 coordinated airport under the retained UK version of Regulation 95/93, at 08:30 on a weekday. Airport Coordination Limited, the UK's independent slot coordinator, has no slot free within an illustrative 15 minutes of that time and offers the next available slot at 10:15 instead. The client can accept the later slot at no extra charge, or reroute to Biggin Hill Airport, an illustrative 24 kilometres away, adding an illustrative £550 ground transfer into central London. Taking the delayed slot costs nothing extra on the invoice; taking the alternate airport adds the £550 transfer to the total.