How Much Connection Time Is Genuinely Safe?

Every airport publishes a minimum connection time, or MCT, for different combinations of arriving and departing flights. Domestic to domestic is usually the shortest. International to international, especially where a passport check sits in the middle, is the longest.

The MCT is calculated by the airport authority based on typical walking distances, typical queue lengths and the layout of security and immigration. It assumes the inbound flight lands on time and that you walk at a normal pace without getting lost.

The MCT is a floor, calculated for a good day. It does not build in the ten minutes a jet bridge takes to connect, the bus that ferries you from a remote stand at Dubai DXB, or the fact that your inbound gate and outbound gate happen to be at opposite ends of a two kilometer terminal.

• Remote stands and bus transfers add ten to twenty minutes that never appear in the schedule.
• A late arrival slot because of air traffic control flow restrictions can eat your entire buffer before you even reach the jet bridge.
• Peak-hour immigration queues at hubs like Charles de Gaulle or Narita can run twenty five minutes even when everything else is normal.
• A gate change announced after boarding closed can turn a five minute walk into a fifteen minute one.

A single number like ninety minutes is a reasonable starting baseline, but it should move depending on where you are connecting. Zurich HB style compact single-terminal airports need less padding than sprawling multi-terminal hubs.

• Add 30 minutes if the connection involves a terminal change reachable only by bus or train.
• Add 30 minutes if hold luggage must be re-checked rather than through-checked.
• Add 20 minutes if you are entering a new immigration zone, such as landing outside Schengen and connecting inside it.
• Add 15 minutes in winter at any airport with a real chance of snow or fog delays.
• Subtract nothing for a connection that is also the last departure of the day; if anything add more.

If both flights are on one ticket, the airline is responsible for getting you to your destination if the connection fails because of their delay. They will typically rebook you on the next available flight and, where required by their own rules or by regulation, cover a meal or hotel.

If you booked two separate tickets, sometimes called a self-transfer, a missed connection is your problem to solve. The second airline owes you nothing if the first flight ran late, because as far as they know you are simply a passenger who did not show up.

Airport websites usually publish terminal maps and, for major hubs, average security and immigration wait times by hour. Ten minutes checking these before booking tells you more than any generic rule of thumb.

Questions worth answering before you book

• Are both flights in the same terminal, or does the connection require a train, such as at Frankfurt or Charles de Gaulle?
• Does the arrival gate typically use a jet bridge, or does the airline commonly use remote stands for that route?
• Is there a security re-screening step between the two flights, which adds time even for people already inside the airport?

If your inbound flight is delayed and your connection is at risk, act as soon as boarding closes on your first flight, not after landing. Cabin crew can often radio ahead, and some airlines will hold a connection for a handful of passengers if enough of you are affected and the delay is short.

• Tell a flight attendant early that you have a tight connection so ground staff can be alerted before you land.
• Move to the front of the queue to disembark if the crew allows it for passengers with a documented tight connection.
• Head straight for the connecting gate rather than a service desk first, since the gate agent can rebook you faster if the flight is still there.
• If you clearly will not make it, go to the airline's transfer desk immediately rather than exiting the secure area.

Summer thunderstorm season in the United States routinely produces rolling delays through Atlanta and Chicago that ripple across the whole network. Winter fog is a recurring issue at London Heathrow and Milan Malpensa. If you are connecting through either region in the relevant season, add time even if the specific flights show no history of delay.

Some regions also run tighter staffing at immigration during off-peak hours, which can paradoxically make a very early morning connection slower than a mid-afternoon one, since fewer officers are on duty to handle the same aircraft loads.