Minimum Connection Times (MCTs): An Insider's Guide

Behind the scenes there are many operations in place to ensure smooth and seamless air travel experiences for passengers, and one aspect is Minimum Connection Times (MCTs) at airports.

Flight connections enable passengers to access new destinations, expanding their travel options, and create new revenue opportunities through codesharing and virtual interlining. In this article, we explain the crucial role MCTs play in ensuring efficient air travel. 

What is a Minimum Connection Time?

Minimum connection times are standardized and agreed data sets that provide the minimum amount of time for passengers (and their luggage) to make a successful connection between flights. They are applied globally to develop and ensure viable connections.

Airlines have in their Contract of Carriage (COC) a defined list of minimum connection times at airports, also known as minimum layover times or legal connection times. OAG handles over 157,000 industry-standard MCTs and airline-specific exceptions – these are then used by global distribution systems (GDS) and connection builders.

There are different types of minimum connection times, as seen in the table below. The differences reflect the physical distances involved, the potential need to go through security or customs control, and the logistical requirements of getting an arriving aircraft ready for the next departure. MCTs could be as low as 30 minutes for domestic, whilst for international flights can be up to an hour and a half to transfer to an international carrier.

MCTs-Explained-1 (1200 × 300 px)

How Are Industry Standard Minimum Connection Times Determined?

All new industry standard MCTs must be approved by IATA. Once the new MCT is established, this becomes the default value for that airport and is used by the entire industry. 

Step 1: The Airport Operators Committee (AOC), consisting of all airlines operating in and out of that airport, agree to a new Minimum Connection Time value.

Step 2: The new MCT value is submitted to IATA for approval.

Step 3: IATA informs the industry of the new MCT value at that airport.

Minimum Connecting Times (MCTs) Explained | View Now

What Are Airport Minimum Connection Time Exceptions?

Airports may choose to set their own Industry Standard MCT, which will override the Status Exception default time for the following reasons:

  • Clear customs or immigration.
  • Move between terminals.
  • Collect baggage.
  • Check-in to next flight.
  • Distance between arrival gate of first flight an departure gate for second flight.

What Is an Airline Specific Minimum Connection Time?

Airlines such as KLM, Emirates, Singapore Airlines and COPA have built extensive networks around connecting traffic and providing the most efficient, fastest MCT possible.

Airlines can file “exceptions” to an airport’s MCT as they seek to secure a competitive advantage; the shorter the connection time, the shorter the total journey time and the flight will appear higher up the search results.

Airline specific connections are flights that are shown in search results from an airline or online travel agency (OTA) website – these specifically display a connection time that meets airline standards. If a passenger fails to make a connecting flight from the originating flight, the airline is responsible. This extends to a passenger’s luggage, if checked bags do not make the connecting flight the airline is held responsible and is expected to arrange courier delivery of the missing luggage to the owner.

Airline specific Minimum Connection Times typically have a higher level of detail than those published by the airport operator. In many cases airline MCTs are different between their commercial partners, frequently are specific to only a defined series of flight numbers and can have both ‘effective from and to’ dates published as part of the exception.

At London Heathrow there are currently 2,372 individual carrier exceptions on top of the airport's own published standards, and at Paris Charles de Gaulle some 10,160 exceptions, as those airports with a broad range of customers tend to have thousands of unique carrier exceptions created as part of commercial agreements.

Multiply the “defaults” and “exceptions” at every airport around the world and it doesn’t take long to realize that there are literally thousands of “defaults” and hundreds of thousands of “exceptions” in the airline industry; many of which are now lapsed or have minimal impact.

Minimum Connection Times Data | Discover Now

What Is an Exception to an Exception?

To display a specific exception by a carrier, sometimes it is necessary to add an MCT exception at the status standard time.

The following is an example of this situation:

The Domestic to International (DI) status standard at MIA is 1 hour>> AA has an exception: AA to ALL carriers at MIA 55 minutes >> AA advises that BA is an exception to this, and that the status standard at MIA should apply.

This will be displayed:

The following identifies the 55-minute exception for all carriers. AA – to All Dom to Int’l exception at MIA 55 minutes.

The following identifies the BA exception to this exception. AA – to BA Dom to Int’l status standard at MIA 9999.

Why Do Minimum Connection Times Matter?

Any missed connection for an airline is an unexpected cost, and when operating margins are quite small, avoiding unnecessary costs must be top of the agenda for any airline. In most cases, a traveler missing a connection can be accommodated on the same day, perhaps on the next flight or via an alternate point. Occasionally though that cannot happen, leading to hotel costs and in some cases further revenue displacement as the traveler occupies a seat that could have been sold to another traveler at short notice and perhaps a higher selling fare.

A potential missed connection can also have longer commercial consequences than just the inconvenience of one traveler. Scenarios where large groups of travelers miss their onward connection multiply the damage, as does the frustration of a high-frequency regular traveler who suddenly decides to place their business with a different airline.

How Can MCT Data Affect Airline Ticket Sales?

Part of the challenge of minimum connection times and codeshares, is synchronizing the schedules of the operating airline and the marketing carrier. 

When any airline makes a schedule change, that schedule change must be picked up by the codeshare airline, sometimes via a direct notification from their partner airline or via OAG. That process allows a “window of opportunity” for a connection to be sold based on the old published data, rather than the new schedule, and that can result in a missed connection or the need for the airline to contact the traveler and advise them of a change in schedule.

Reviewing MCTs regularly will ensure that connections are not affected by changes to the schedule. If you are an existing MCT supplier, using the new features may reduce the amount of MCTs you need to maintain making it easier for you to file with ease and regularity. 

The accurate presentation of total journey times is crucial. Whilst many systems allow passengers to sort flight options by price; for many the default parameter has always been the total elapsed journey time. 

Every GDS and OTA has their own unique algorithm for calculating the most effective connection and therefore the highest placed routing. Subtle changes by airlines to their MCTs, adjustments by flight number to protect lucrative traffic flows and changes to elements of flight schedule data records can create highly complex data challenges and that’s before the introduction of the codeshare airline!

OAG and MCTs – How We Support the Travel Ecosystem

Recent changes to MCT processing standards (such as Suppressions and Codeshare Indicators) have resulted in airlines’ requiring increasingly complex management of MCT suppressions, exceptions, and data accuracy; of course, MCTs must be filed correctly to ensure flight connections, and ultimately ticket sales, are successful. This is where OAG comes in.

As leaders of the MCT working group at IATA, our data management teams have been at the forefront of the transition to new data standards to ensure flexibility and consistency across channels and carriers. By providing technical resource, testing capabilities, and guidance to Airlines, OAG has helped make it easier than ever for airlines and airports to supply the correct MCTs to the industry.

Find out more about our Minimum Connections Times data here >>

What is Reference Data / Master Data?

Facilitating the Air Travel Industry

Critical IATA-standard industry codes facilitate air travel and are used to avoid inconsistencies due to the high volume of schedule changes.

MCTs (Minimum Connecting Times) are standardized and agreed data sets that provide the minimum possible connecting time for both a passenger and their luggage to connect between an arriving flight and their departing flight. They are applied globally to develop and ensure viable connections.

IATA industry codes provide universal abbreviations to facilitate travel and enable a common language to be interpreted and understood across systems all over the world. They are typically 1, 2, 3, or 4-character combinations that uniquely identify locations, equipment, carriers, and times to standardize international flight operations. This reference underpins the system and whilst it doesn’t change as often as schedules, any change however small can impact the integrity of schedules information. This impact affects search and booking volumes, connection viability and the smooth running of the ever-increasing code share partnerships across the industry.

What Types of IATA Codes Exist?

Airline Codes

IATA administers the two-letter airline code and once it is assigned, OAG advises IATA of ports and equipment codes used by the carrier in its schedule. OAG adds an ICAO code where applicable as well as maintaining ICAO codes for airlines that do not have an IATA code to enable their schedules to be distributed.

IATA will also advise when codes are recalled for reasons such as an airline ceasing operations.

Locations and Time Zones Data

IATA administers the three-letter codes and advises any changes. Typically, this is when an airline starts operating to a new location. These coordinates need to be validated (or added when not supplied), names verified, and ICAO codes assigned. The locations are sent to a country with associated time zone and DST info. The location may also be attached to a city as part of a metropolitan area e.g. NRT and HND assigned to TYO (Tokyo).

There are currently over 11,000 IATA codes – 7,249 have also been assigned ICAO codes. There are 4,200 locations that are considered active.


OAG maintains equipment data for all scheduled services. Data is sourced from aircraft manufacturers and includes: ICAO code, Body Type, Aircraft category e.g. jet engine, Maximum speed and range and maximum take-off weight.

Aircraft data is maintained at three levels - configuration at equipment and service type, for an airline’s fleet, as supplied by carriers in their schedule data i.e. at flight and route level.

More in this series: 

Flight Status Data| Read Our Insider's Guide

SSIM Data| Read Our Insider's Guide