A legal connection is not a comfortable one
When an airline sells you a connecting itinerary on one ticket, the connection has to meet a minimum connecting time for that airport. These minimums are set for each airport, and sometimes each terminal and type of connection, and they reflect how long it normally takes to get from one flight to the next. If an airline sells the connection, it considers it achievable.
Achievable is not the same as comfortable. A minimum connection assumes the first flight arrives on time and that you move briskly. It does not account for a slow deplaning, a long walk between terminals, or a queue at passport control. You are allowed to choose a longer layover than the minimum the airline will sell.
One ticket or two tickets
The most important question about any connection is whether both flights are on the same booking. On a single ticket, if the first flight is late and you miss the second, the airline is responsible for getting you to your destination, usually on the next available flight. Your checked bags are normally transferred for you.
On separate tickets, each airline is responsible only for its own flight. If the first is late and you miss the second, the second airline can treat you as a no-show, and you may need to buy a new ticket. You also usually have to collect your bags and check them in again, and you may need to leave the secure area to do it. Search sites sometimes combine separate tickets into a cheaper itinerary. Google's help notes that cheaper results can include a self-transfer of luggage between flights. That can be good value if the gap is long and you understand the risk. It is a bad surprise if you thought you had bought one trip.
How to see the split
Look for words like self-transfer, separate tickets, or a warning that bags are not checked through. If the checkout shows two confirmation numbers, you have two contracts. Price a protected single ticket beside it before you decide the split is worth the discount. The bag and seat math in the true cost of a fare belongs in that comparison, because a self-transfer often means reclaiming a checked bag and paying to check it again.
Passport control changes the clock
Connections that involve entering a new country take longer. U.S. Customs and Border Protection explains that travelers arriving in the United States clear inspection at the port of entry. On many itineraries that means your first U.S. airport, even if you are connecting onward, and you may need to collect and recheck bags. Similar processes apply in other countries. Build more time for these connections than for a domestic transfer in one terminal, and check whether you need a visa or transit authorization for the connecting country before you buy a tight layover there.
Preclearance and sterile international transfers exist in some places, so do not assume every connection works the same way. Read the airport's own transfer guide for the terminals on your ticket. A connection that looks short on a map of the city can be long once you include the immigration hall.
How to read a layover before you buy it
Look at the airport and the terminals. A connection within one terminal is usually quicker than one that requires a train or bus between terminals, or a change of airport entirely. An airport change is not a connection. It is a second ground trip, and it belongs in the same worksheet as alternate airports.
Consider the time of day and the season. Winter weather and summer storms cause more delays, and the last connection of the day leaves no same-day backup if you miss it. Consider your own pace. Travelling with small children, needing wheelchair assistance, or carrying a lot of hand luggage all make short connections harder. It is reasonable to choose a longer layover even when a shorter one is available. The extra hour is often cheaper than the missed flight.
The last flight of the day
If the onward flight is the last one, or the only one, a minimum connection is a bet that the first flight will be early or exactly on time. When that bet matters, because of a cruise, a wedding, or a separate ticket the next morning, add a longer buffer or an overnight stop. An overnight you chose is a hotel you can book. An overnight the airline assigns you after a miss is a different evening.
If you are running late
Tell the cabin crew before landing if you have a tight connection. Sometimes they can help you leave the aircraft sooner or tell you the gate. Check the airline's app, which often shows the new gate and, if you have been rebooked, the new flight. If you miss the connection on a single ticket, go to the airline's transfer desk or use the app rather than joining a general check-in queue.
On a single ticket covered by EU261, a missed connection caused by a delay on an earlier flight can lead to compensation if you arrive at your final destination three hours or more late and the delay was within the airline's control. The details are in EU261 explained. In the United States, airlines publish commitments in their customer service plans about meals and hotels when a delay or cancellation is within their control, and the DOT refund rules apply when a change is significant and you decide not to travel.
Short connection or long one
Short connections reduce total travel time, and on a single ticket the airline carries the risk of a miss. Longer connections cost time but give you a buffer, a chance to eat, and sometimes more rebooking options if several flights a day continue to your destination. If there is only one onward flight, the short connection is riskier than the clock suggests.
If you do not yet know an airport, err on the generous side. Frequent travelers develop a personal minimum for places they know. Until you have that experience, the published minimum is a floor, not a target. Save the airline's app and phone number before you travel so you can act if the first flight slips.
Before you accept the itinerary
Check that both flights are on one booking if you want the airline to protect the connection. Note whether the connection involves a terminal change, an airport change, or immigration. Compare the layover with how you actually move, not with an ideal walk. Think about the season and whether this is the last flight. Then decide. A connection you understood before you paid is a plan. A connection you discovered on the boarding pass is a risk you did not price. When you are ready to look again, use the flight search and open every layover before you sort by duration.
