Connecting flights and online check-in

The fundamental split: one ticket vs two

Everything about connecting flights flows from this one fact: are your two flights on a single booking reference (one ticket) or two separate bookings (two tickets)?

• One ticket (interlined or codeshare) — the airline guarantees the connection. They'll rebook you free if you misconnect, and your bags through-check to the final destination.
• Two tickets ("self-connect") — you saved money, but the airlines are not aware of each other. If the first leg is late, the second airline can charge you a no-show fee. Bags must be claimed and re-checked between flights.

Online check-in behaves accordingly: one ticket means one check-in flow that issues both boarding passes; two tickets means two separate check-ins, often opening at different times.

One ticket — the through check-in

1. Check-in opens at the first leg's window

   If the first leg opens 24 hours before, that's when you check in for the whole journey — even if leg 2 wouldn't normally open for another 12 hours.

2. You get one or two boarding passes

   Most airlines issue both at once. Some (notably US carriers connecting through their hubs) only print the second pass after you re-clear security mid-journey. Don't panic if leg 2's pass is missing — there's a kiosk at the connecting airport.

3. Bags are through-tagged

   The bag tag shows your final destination, e.g., LHR-AMS-LAX. The handler at LHR sees AMS as the connecting airport and routes your bag accordingly. You don't touch it again until the final belt.

4. Connection times are airline-validated

   If the airline sold you the itinerary, their system already verified the connection meets the airport's minimum connection time (MCT). If they delay you and you miss leg 2, they rebook you free.

Two tickets — the self-connect

1. Two separate check-ins

   Use airline A's site for leg 1, airline B's for leg 2. Each one opens on its own schedule. Save both boarding passes to your phone.

2. Bags do not through-check

   Even if both flights are on the same physical airline, two booking references means you collect bags at the connection, walk to departures, re-check them with airline B. Build at least 3 hours into the connection — 4 if the connecting airport requires border re-clearance.

3. Re-clear security and (usually) immigration

   You exit airside, enter the terminal, possibly clear immigration, re-check bags, re-clear security. In a Schengen-to-Schengen connection this is faster (no immigration). Anywhere else, it's the full sequence.

4. Missed-connection risk is yours

   If leg 1 is late and you miss leg 2, the second airline treats you as a no-show. You buy a new ticket. Travel insurance with "missed connection" cover is the cheapest hedge — about €15–€30 per trip.

Minimum connection times by airport

MCT is the airport's published minimum connection time. The airline only sells one-ticket itineraries that meet it. Self-connectors should pad it generously:

• Schengen → Schengen — 30–45 min MCT, pad to 90 min.
• Domestic-to-domestic in same hub — 30–60 min, pad to 90 min.
• International → International — 60–90 min, pad to 150 min.
• International → Schengen (with immigration entry) — 90–120 min, pad to 180 min.
• Heathrow Terminal 5 → 3 (BA-to-AA, walk + bus) — 90 min MCT, pad to 150.
• JFK between terminals — 90 min MCT, pad to 180 because of inter-terminal shuttles and re-clearing.

Codeshare connections — easier than they look

If your itinerary is "operated by [partner]" but sold under one airline's flight numbers, it's still one ticket. Through-check rules apply. Check in on the operating carrier's website (see the when check-in fails guide for partner-flight troubleshooting).

Examples:

• Lufthansa LH-coded flight operated by United → check in on United, but the itinerary is one Lufthansa booking.
• BA-coded flight operated by AA → check in on American Airlines, bags through-check, OneWorld lounges available.
• Qatar QR-coded flight operated by Iberia → check in on Iberia, bag tag may say "QR/IB", boarding pass is Iberia branded.

What if leg 1 is delayed?

1. One ticket — relax (somewhat)

   If you miss leg 2, the airline rebooks you on the next available flight free. EU 261 / DOT obligations apply: meals if you wait >2 hours, hotel if overnight. You don't need to do anything until you land — gate staff at the connection point usually have your rebooking ready.

2. Two tickets — act fast

   The moment you know leg 1 is delayed enough to threaten leg 2, call airline B and explain. Some allow free same-day standby on a later flight if you're a status member; most charge a change fee but waive the fare difference. Buying a fully-flex ticket on leg 2 is the safety net for self-connectors.

Visa requirements at the connecting airport

Most airline IT systems check whether your nationality needs a transit visa. If they don't catch it, you do.

• UK — direct airside transit visa (DATV) needed for several non-EU nationalities even without leaving airside.
• USA — no airside transit; you must clear immigration even if connecting. ESTA or visa is mandatory.
• Canada — eTA required for visa-exempt nationals connecting through Toronto/Vancouver.
• Schengen — airside transit is free for most; some nationalities need an ATV for any Schengen airport.
• Russia, China, Saudi Arabia, India — all have specific transit-visa rules; check the embassy site of the connecting country.

If you don't hold the right transit visa, online check-in often blocks you from receiving a boarding pass for leg 1.

Lounge access on connections

If you have status (Star Alliance Gold, OneWorld Sapphire/Emerald, SkyTeam Elite Plus) the lounge applies to your operating-carrier alliance lounge at the connection. Star Gold flying United through Frankfurt? Lufthansa Senator Lounge. OneWorld Emerald flying BA through DFW? American Admirals Club.

For Priority Pass / DragonPass / Amex Centurion, lounge access is independent of the airline. Check the lounge's terms — many limit you to 3 hours and don't allow re-entry.

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