Each year, over 1.5 billion passengers - 43% of global traffic - depart from over 200 slot coordinated airports. The number of slot coordinated airports is expected to grow significantly due to a lack of expansion in airport infrastructure to cope with increasing demand.

IATA is at the forefront of ensuring a fair, neutral and transparent allocation of airport slots at the worlds’ most congested airports through the application of the Worldwide Airport Slot Guidelines (WASG).

New page: COVID-19: Slots!

We have collected all airport slots and COVID-19 related information on our new page, COVID-19: Slots. On the page you can find more information on the work we are doing during the crisis as well as additional resources.


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The Worldwide Airport Slot Guidelines (WASG), provide the industry with a single set of guidelines for airport slot management and allocation. The slot planning process is the essential back bone to allow the industry to plan operations to the world’s most congested airports, avoiding what would otherwise be chaos.

IATA is actively involved in a range of activities including:

  • Working with governments and regulators to promote and align policy with the WASG.
  • Working together with Airports Council International (ACI) and the Worldwide Airport Coordinators Group (WWACG) to ensure slot policy and processes evolve but remain a practical, harmonized, neutral, non-discriminatory and effective solution to managing airport capacity shortage.
  • Supporting the implementation of one single global standard.
  • Running the twice-yearly Slot Conference to allow airlines and coordinators to meet face-to-face to review their slot portfolio and finalize their future schedules.

Visit our FAQ section for more information.


To contact us, please email: slots@iata.org

Worldwide Airport Slots and IATA Committees and Work Groups

Slot Policy Working Group (SPWG)

The Slot Policy Working Group is the industry group responsible for guiding IATA’s slot policy and strategic direction, and providing technical guidance on scheduling and slot related matters. This group brings together the airline slot community to discuss and define response to key issues, policies, emerging trends as well as to identify and set out the priorities for action. The group is also the airline industry’s voice for maintaining the Worldwide Airport Slot Guidelines (WASG). The SPWG meets four times a year, including at both Slot Conference events.

Main functions of the SPWG:

  • Set the airline direction and policy on all issues related to the slot process
  • Provide guidance on future initiatives and strategy
  • Liaise closely with other industry associations and regional groups linked to airport slot activities


The SPWG is drawn primarily from the IATA Member airlines slot community, SPWG membership is typically comprised of senior experts in slot management policies and procedures and/or airline scheduling.

Non-IATA Airlines may wish to be considered for the role of rapporteur to the SPWG, and IATA welcomes and encourages their participation in the SPWG in such role.

The SPWG term runs for three years, starting in September. The next opportunity for nomination is for the 2022 term.

Membership: Slot Policy Working Group.

Terms of Reference: Slot Policy Working Group.

Worldwide Airport Slot Board (WASB)

Airports Council International (ACI), the International Air Transport Association (IATA) and the Worldwide Airport Coordinators Group (WWACG) agreed a new industry-wide governance structure that will provide an equal role to airports, airlines and coordinators in continuously reviewing and enhancing the slot guidelines.


The Worldwide Airport Slot Board is established as a joint forum of airports, airlines and coordinators to govern the newly renamed Worldwide Airport Slot Guidelines (WASG). The WASB mandate is to:

  • Propose areas of policy development;
  • Consider ways of improving the procedures;
  • Review and analyze future trends and technology;
  • Approve changes to the WASG, and
  • Establish Airport Slot Working Groups (ASWGs).

The ASWGs are groups comprising of airports, airlines and coordinators created to develop technical recommendations for consideration and approval by the WASB, and to develop and support the implementation of the WASG.


The WASB is comprised of seven airports, seven airlines, and seven facilitators/slot coordinators appointed by ACI World, IATA and WWACG for a three-year term.


Membership: Worldwide Airport Slot Board (pdf)

Terms of Reference: Worldwide Airport Slot Board (pdf)

Contact Details

For queries regarding the SPWG and WASB, please contact slots@iata.org

Worldwide Airport Slots works with:
The Industry Affairs Advisory Council (IAAC), Plan Standards Board, Architecture and Technology Strategy Board (former PADIS)

In June 2016 IATA initiated a Strategic Review of the Worldwide Slot Guidelines to identify the areas where the WSG (since then renamed to Worldwide Airport Slot Guidelines, WASG) could be modernized. IATA invited Airports Council International and Worldwide Airport Coordinators Group to join the review in order to ensure total industry participation from all the stakeholders in the improvement and optimization of the WSG, as one single global slot process.

In June 2017 four task forces were created to work on a set of recommendations for changes and enhancements to the WSG where necessary. The review was completed in late 2019, and the respective amendments published in the WSG Editions 9 and 10 following industry approval.

Objectives of the Strategic Review

  • Strengthen the principles of the WSG
  • Ensure policy and procedures remain relevant
  • Reinforce the benefits of the single global process
  • Better take advantage of new technologies

The Task Forces

  • Airport Levels - looking at how to ensure that airports that are currently not congested (or at least not congested all the time) can continue to grow and provide the connectivity and services that consumers want without having to impose the complex allocation processes that have to be used for fully congested (Level 3) airports
  • Historic Determination - reviewing the current processes involved in retaining slots and how to ensure best use of scarce capacity to promote connectivity and choice to the customer
  • Slot Performance Monitoring – how best to ensure that airlines use their slots as allocated, without penalizing airlines for unforeseen ‘on the day’ operational factors (e.g. air traffic control congestion, tech aircraft, strikes or bad weather)
  • Access to Congested Airports – looking at enhancing the process for allocating slots to airlines wishing to get access to congested airports, whilst maintaining transparent and clear rules for all

WSG Strategic Review 2019 update - summary of the changes to the WSG

The changes as a result of the work of the task forces were published in the 9th and 10th editions of the WSG. To learn more about the changes and enhancements to the WSG please visit the Strategic Review Fact Sheet (pdf) or the Overview of changes paper (pdf) for more information.


To contact us, please email: slots@iata.org

Airport Slot Coordination Training 

Widen your expertise and participate in one of our training courses! We offer two courses focusing on airport slots, the Airport Slot Management and Coordination course and our new course, Airport Slot Coordination: Policy and Implementation. You can attend both slots training courses also as virtual classroom courses.

Airport Slot Mangement and Coordination

Due to the growth of air traffic’, some airports are experiencing a discrepancy between available airport capacity and demand. Coordination involves the allocation of constrained or limited airport capacity to airlines and other aircraft operators to ensure a viable airport and air transport operation. Coordination is also a process to maximize the efficient use of airport infrastructure. This course will help you learn how to allocate and coordinate airport slots by applying the Worldwide Airport Slot Guidelines (WASG), the accepted global standard for airport slot allocation.

What you will learn

  • Allocate slots according to the requirements and procedures for either facilitated (level 2) airports or coordinated (level 3) airports
  • Apply the standard procedures for communication between airlines and slot coordinators
  • Maximize your slot portfolio management capabilities
  • Apply slot procedures and understand the impact of international rules and regulations
  • Execute slot messages in compliance with SSIM Chapter 6
  • Analyze capacity constraints and historic slot eligibility

See course page for more information and registration!

Airport Slot Coordination: Policy and Regulation (NEW!)

The aviation industry faces enormous challenges as a result of insufficient airport infrastructure across the globe. The Worldwide Airport Slot Guidelines (WASG) help the industry to meet ever-growing consumer demand for such infrastructure. The Airport Slot Coordination: Policy and Implementation course will provide you with an enhanced and balanced understanding of these challenges as well as the principles that have been developed to meet demand in a fair, transparent, and neutral way while promoting the most efficient use of scarce airport capacity.

What you will learn

  • Describe the global context of schedule planning in a constrained airport environment and how it relates to connectivity, competition, and consumer benefits of aviation
  • Explain the challenges posed by insufficient airport infrastructure
  • Detail the principles and objectives of the Worldwide Airport Slot Guidelines Justify the need for transparency, flexibility, sustainability, certainty, and consistency in airport capacity allocation
  • Advocate for the optimization of scarce airport capacity

See course page for more information and registration!

These courses are available at IATA Training Centers, regional training partner locations, and on-demand as in-company training

Testimonials ​for the Airport Slot Management and Coordination Course


Adam Mohamed - IOC Senior Operations Controller - Gulf Air

Gulf AirI attended the 3 day’s Airport slots and coordination classroom course to further expand my knowledge in the aviation field. I did anticipate difficulties in completing this course especially in such a short timeframe. However, the instructor taught in such a way the information was passed clearly, whereby we not only understood the content but were also able to apply this knowledge beneficially upon returning to duty.
I would recommend from my personal experience this course for anyone in the aviation Industry.​

Liva Ozolina - Scheduling and Slot Manager - AirBaltic

Air BalticEven though I have been working with slot handling messages and WSG for few years now, this course was very useful for strengthening my knowledge and for learning new specific details with well though examples on respective cases. I would suggest this course for everyone whose daily work is related to airport slots.​

​Md Ashraful Haque - Manager Operations-Schedules Planning - Biman Bangladesh Airlines

Biman Bangladesh AirlinesThough I had some previous hands-on experience on Airport Slots and Coordination procedures but in some critical cases I experienced some situations when it would get very difficult for me to find a solution. A sincere thanks to IATA for arranging such an advantageous course, which gives a clear idea about ins and outs of the airport slot coordination.
The course covers a wide range of information about scheduling guidelines and slot handling procedures.

Slot Conference Questions

When and how often are Slot Conferences?
Slot Conferences are held twice yearly. The conference dealing with northern winter period is held in June and the conference held in November deals with the northern summer period for the following year. the Slot Conference web page details future events.

How did the Slot Conference come about?
Since 1947, under the auspices of IATA, airlines have met regularly to discuss their slot allocations planned for the following season in order to improve interline connections and handling arrangements.

Primarily through bilateral discussions, they voluntarily adjusted their slots where it was in their mutual interest to do so. Their main objective was to return home with firm slot allocations that triggered the various preparations that were needed to operate them.

With the onset of congestion at a few major airports in the early 1960s, the scope of the slot allocation discussions was broadened to cover the adjustments needed to reduce anticipated delays to an acceptable level.

In instances where airport services that were planned during certain periods exceeded what the airport could accommodate, some services would have to be moved, usually with some economic penalty. Over the years, a consensus developed as to which services should be moved, in fairness to all those who were planning to operate during the period.

The recommended procedures and priorities for such slot adjustments are contained in the Worldwide Airport Slot Guidelines. 

Who can attend Slot Conferences?
Airlines licensed to operate air services or have applied for a license to operate air services. Coordinators from slot-coordinated airports (Level 3 airports) provided they have been approved by their government, and facilitators from facilitated airports (Level 2 airports) provided they have been appointed by the appropriate authority.

Can non-airline personnel attend Slot Conferences?
Conference policy permits only airlines, coordinators and facilitators to attend conferences. However, in the case of government officials, airport operators or their representatives or any other non-airline representatives, exceptions may be granted by IATA for the purpose of familiarization and normally for one conference only. Non-airline personnel wishing to be invited to a Slot Conference should send their request to IATA Management at least 30 days in advance of the Conference they wish to attend.

Can a delegate represent more than one company at the Slot Conference?
A participant can be accredited on behalf of more than one organization.

Can a company act on behalf of another company at the Slot Conference?
In the context of mergers, subsidiaries, service contracts or alliances: One registration is required for each AOC / coordination agency. A participant can be accredited on behalf of more than one company/ agency.

I have a proposal for a future venue for the Slot Conference. Where can I find the criteria for a suitable site?
If you would like information on hosting the Slot Conference, or have a proposal for a future venue please email IATA Management for the Slot Conference Handbook. This document lists the Slot Conference logistical and technical specifications required to produce this business meeting

Slot Committees Questions

I am interested in becoming a member of the Slot Policy Working Group (SPWG). What must I do to be considered for membership?
Only IATA Member airlines are eligible for participation in SPWG. Members of the SPWG are appointed by the Director General of IATA. Individuals interested in becoming members of the SPWG should send a curriculum vitae together with a letter of support from the CEO of his/her organization to:

Lara Maughan, Head of Worldwide Airport Slots
IATA Centre,
Route de l'Aéroport 33, P.O.Box 416
CH-1215 Geneva 15 Airport,

I am interested in becoming a member of the Worldwide Airport Slot Board (WASB). What must I do to be considered for membership?
The Worldwide Airport Slot Board is a joint forum comprised of seven airline members, seven airport members and seven coordinators. The seven IATA airline members are appointed by the IATA Director-General from the membership of the Slot Policy Working Group (SPWG).

How can I subscribe to the IATA Standard Schedules Information Manual (SSIM)?
Subscribe to the IATA Standard Schedules Information Manual (SSIM)
Copies of the current edition of the IATA Worldwide Airport Slot Guidelines are available in pdf format and can be downloaded free-of-charge from the IATA WASG webpage

Slot Allocation Process Questions

When do the summer and winter periods of slot allocation begin?
The northern summer season begins on the date of Daylight Saving Time (DST) introduction in European Union countries, which currently always takes place on the last Sunday in March. The northern winter season commences on the date Daylight Saving Time (DST) ends in European Union countries, which currently always takes place on the last Sunday in October.

Where can I find a list of Facilitated (Level 2) and Coordinated (Level 3) airports?
The Annex 12.7 (Contact list for Level 2 and Level 3 airports) (xls) of the Worldwide Airport Slot Guidelines (WASG) contains a complete list of facilitated (Level 2) and coordinated (Level 3) airports along with the TTY and e-mail contacts for the facilitators/coordinators responsible for each airport.

Who do I contact, if I wish to commence operations to a Non-Coordinated airport (Level 1)?
Airlines with traffic rights permitting them to operate to a Level 1 airport should notify their appointed handling agent and the relevant airport managing body, or the data collecting agent if one has been appointed, of their planned operations.

Who do I contact, if I wish to operate to a Facilitated airport (Level 2)?
Airlines operating to, or intending to operate to a Facilitated (Level 2) airport must submit their proposed operations to the Facilitator of the airport concerned. Details of the format used in exchanging data with the facilitator are shown in SSIM Chapter 6 of the Standard Schedules Information Manual (SSIM).

Who do I contact, if I wish to operate to a Coordinated airport (Level 3)?
Airlines operating to, or intending to operate to, a Coordinated (Level 3) airport must submit their proposed slots to the Coordinator of the airport concerned. Details of the format used in exchanging data with the facilitator are shown in SSIM Chapter 6 of the Standard Schedules Information Manual (SSIM).

What is a slot?
A slot is defined as the scheduled time of arrival or departure available for allocation by, or as allocated by, a coordinator for an aircraft movement on a specific date at a coordinated airport.

When can I expect to receive confirmation of the historic slots held by my airline at various airports?
The Slot Historical and Non-Historical Allocation Lists (SHLs) must be distributed for each airport, as soon as the historics have been determined by the coordinator, but not later than: the third Monday in April for what is on record as historical slots, as actually operated in the preceding Northern Winter period; the third Monday in September for what is on record as historical slots, as actually operated in the current Northern Summer period up to that time. It must be noted that information given to airlines prior to the end of the Summer period must be regarded as provisional until the season is completed.

Prior to the Winter and Summer Slot Conferences, when must I submit my Slot Clearance Requests (SCRs)?
Airlines must submit their Slot Clearance Requests (SCRs) to the appropriate Coordinators and their Schedule Movement Advices (SMAs) to the appropriate Facilitators by 23:59 UTC on the 30th day prior to the start of the Slot Conference.

Having submitted my SCRs to the appropriate coordinator, when can I expect to receive information on the status of my requested slots?
Coordinators must inform relevant airline delegations of the status of all their requested slots as soon as possible but not later than 23:59 UTC on the 9th day prior to the start of each Slot Conference using the Slot Preliminary Allocation List (SAL) message.

If an airline becomes aware that for whatever reason it may not be able to use an allocated slot or series of slots, what must it do?
The airline must immediately advise the coordinator and return any slots it knows it will not use. In particular these slots must be returned no later than 31 January for the next Northern Summer period and no later than 31 August for the next Northern Winter period.

What is meant by a series of slots?
A series of slots is defined as at least five slots having been requested by an airline at an airport for the same time on the same day of the week regularly in the same period and allocated in the same way, or if that is not possible, allocated at approximately the same time. The expression 'same time' in this context means within the same coordination parameters.

What is the difference between the terms 'use-it-or-lose-it' and the '80-20 rule'?
Both terms are intertwined and refer to a requirement for airlines to operate at least 80% of their allocated slots to their coordinated timings or face the possible loss of historical precedence for those particular slots in the next equivalent season. Conversely, if an airline fails to operate no more than 20% of their allocated slots to their coordinated timings, the airline will retain historical precedence for its slots in the next equivalent season.

When is an airline considered to be a 'new entrant' at an airport?
A 'new entrant' is defined as an airline requesting a series of slots at an airport on any day, where if the airline's request was accepted, it would hold fewer than seven slots at that airport on that day.

Only airlines can be eligible for new entrant status. Of the slots contained within the slot pool at the initial allocation, 50% must be allocated to new entrants, unless requests by new entrants are less than 50%.

The coordinator shall treat requests of new entrants and other airlines fairly, in accordance with coordination periods of each day. Other criteria for allocating slots from the pool are secondary to this criterion. An airline’s slot request should have new entrant status provided that the request, if accepted, would result in the airline holding fewer than seven slots at that airport on that day.

An airline must not claim new entrant status if it intends to operate on an ad hoc basis. A new entrant, who has been offered slots within one hour before or after the time requested, but has not accepted this offer, will not retain new entrant status for that period.

Airlines shall inform the coordinator, at the time of the request for allocation, whether it would benefit from the status of new entrant in respect of the requested slot. If new entrants are dissatisfied with the response to their slot request, they may ask for a meeting of the appropriate coordination committee to consider the situation.

Is a Coordinator obliged to provide data from its database to any airline requesting such information?
In the interests of fairness and transparency, coordinators must make available, upon request, the following information for review by all interested parties: (a) Historical slots by airline and chronologically for all airlines. (b) Requested slots (initial submissions) by airline and chronologically for all airlines. (c) All allocated slots, and outstanding slot requests, by airline and chronologically for all airlines. (d) Remaining slots available. (e) Comparisons between (a) and (c) above by time interval coordinated and by airline. (f) Full details of the constraints being used in coordination. (g) Full details of the criteria being used in the allocation of slots.

What guidelines apply for the transfer of slots from a recently purchased airline?
From the WASG perspective a transfer of slots is allowed with the following stipulations: (a) Transfers may only take place where they are not prohibited by the laws of the relevant country, (b) Slots may only be transferred to another airline that is serving or planning to serve the same airport, (c) The slots being transferred must have been operated for two equivalent periods and (d) These types of transfers should involve the airport coordinator for final confirmation. Further information can be found in section 8.12 of the Worldwide Airport Slot Guidelines - WASG.

SSIM Questions

Where can I find information on UTC (Universal Time Coordinated) Standard and Daylight Saving Time variations from local time?
Appendix F of the IATA Standard Schedules Information Manual (SSIM) provides UTC Standard and Daylight Saving Time-Local Time variations for each country where regular scheduled services operate.
How can I be informed of the latest changes to DST application?
UTC (Appendix F) notifications are available on SlotLink for all SISC participants
UTC notifications are distributed to subscribers of the SSIM

What is a Minimum Connecting Time (MCT)?
For the purpose of Resolution 765, in a passenger context, a Minimum Connecting time (MCT) interval is defined as the shortest time interval required in order to transfer a passenger and his luggage from one flight to a connecting flight, in a specific location or metropolitan area. In a cargo context, the MCT can be defined as the shortest time interval required in order to transfer cargo shipment from one flight to a connecting flight.

MCT intervals are also referred to as ‘official’ or ‘standard’ MCTs. Bilateral MCT agreements, and online connecting time intervals established by a carrier that differ from the industry MCTs, are known as ‘MCT exceptions’.

MCTs must be observed by all ticketing and reservations outlets all over the world and also are used as input for automated reservations systems.

How are MCTs established or modified?
Establishment of and changes or exceptions to standard MCTs are governed by the provisions of IATA Resolution 765 Official MCTs are determined by the airport local MCT group, which consist of scheduled airlines and railways serving an airport, or if there is no such a group, by the Airport Operating Committee (AOC). Once IATA has been informed by such a group of the setting of, or changes to, existing official MCTs, IATA notifies the Scheduling community (including IATA partners such as CRS/GDS/schedule aggregators) of the changes by posting them on the IATA SlotLink.

How can I be informed of the latest changes to MCT?
MCT industry notifications are available on SlotLink for all Airline professionals.

How are MCT exceptions established or modified?
Official MCTs are used by default. Airlines may decide to deviate from the official MCT in a given airport by publishing a MCT exception. When two airlines are involved, connecting time exceptions, if required, are usually established on a bi-lateral basis. These exceptions to MCTs are generally less than the airport official MCTs and are basically marketing agreement between airlines, or exception within an airline’s own air service. It is the airline's responsibility to set realistic connecting times to allow for connections of passengers and baggage. Carrier exceptions need to be filed with the main data aggregators, as well as with the GDS when applicable.

How does a Local Airport MCT group inform IATA of changes to the MCTs?
The Local Airport MCT Group Chairman shall communicate MCT changes to the IATA Worlwide Airport Slots Department by email.

Where can I get MCT tables?
MCT tables are available from the Schedule reference Service (SRS)

How can I order a copy of the IATA Worldwide Airport Slot Guidelines (WASG) and how much does it cost?
The WASG is freely available from the WASG webpage and has been translated into several languages. Although, if inconsistencies arise with other translations the English version always takes precedence.