The Problem With Assuming One Airport Means One Building

When you book two separate flights and both say "LAX" or "LHR," it's natural to assume you'll land and depart from the same area. That assumption can cost you a connection. Many major airports are divided into multiple terminals — sometimes physically separated by a bus ride, a train, or even a short drive — and airlines don't always share the same one.

This gets more complicated when a single city is served by multiple airports entirely. In London, LHR (Heathrow) and LGW (Gatwick) are about 30 miles apart. Booking one flight into LHR and a second out of LGW is a recipe for panic if you didn't realize they were different airports. The same applies to New York (JFK, LGA, EWR), Tokyo (NRT, HND), and Chicago (ORD, MDW).

Before you finalize any itinerary with two separate tickets, check whether both flights use the same airport code — and whether that airport has multiple terminals with limited connections between them. See our breakdown of connecting flight tradeoffs for context on when this risk matters most.

How to Read Terminal Information Before You Fly

Airport codes follow the IATA three-letter system (used on tickets and boarding passes) and the ICAO four-letter system (used by air traffic control). As a traveler, you'll almost always see IATA codes — the three-letter ones like ORD, CDG, or SYD.

Terminal information is separate from the airport code and appears in a few places:

  • Your booking confirmation or e-ticket — look for a "Terminal" field next to departure or arrival details.
  • The airline's website — search for your flight number plus the airport name to find terminal assignments.
  • The airport's official website — most publish terminal maps and inter-terminal transport options.
  • Check-in notification emails — airlines often send terminal reminders 24 hours before departure.

Terminal assignments can change up to a few days before your flight, so verify again the day before you travel. If your itinerary has a layover, the flight itinerary guide explains exactly which fields to look at.

Same Code, Different Terminal: A Common Gotcha

Some airports use sub-codes to distinguish terminals — for example, London Heathrow uses LHR for all terminals, but some booking systems display T2, T3, T4, or T5 separately. Always look for the terminal number alongside the airport code, not just the three-letter code alone. If your booking confirmation doesn't show a terminal, check directly with the airline at least 48 hours before departure.

When a Terminal Change Means a Tight Connection

The real danger occurs when you're connecting between two flights booked on separate tickets — for example, a budget airline landing at Terminal 1 and a mainline carrier departing from Terminal 5. Unlike a single itinerary booked through one airline, no one is legally obligated to hold the second flight if you miss it due to a terminal transfer. You'd need to rebook at your own expense.

Some airports publish minimum connection times (MCTs) for inter-terminal transfers. These are guidelines, not guarantees — security lines, passport control, and crowded shuttle buses can all add time. A general rule of thumb: allow at least 90 minutes for same-airport terminal changes, and at least 2–3 hours when those terminals involve different security checkpoints or customs.

If you're arriving internationally and departing domestically (or vice versa), factor in customs and immigration — that alone can add 30–60 minutes at busy airports. Time zone confusion is another variable that can shrink your actual layover window without warning.

Once you land and clear the terminal, you'll also need to orient yourself in an unfamiliar arrival area. The guide to navigating city arrivals covers what to do in those first disorienting minutes.

IATA code

A three-letter code assigned by the International Air Transport Association to identify airports (e.g., ORD for Chicago O'Hare). This is the code you'll see on tickets, boarding passes, and booking sites.

Terminal

A separate building or section within an airport where passengers check in, board, and arrive. Large airports may have multiple terminals that require a bus, train, or walkway to travel between.

Minimum Connection Time (MCT)

The shortest amount of time an airport designates as sufficient to transfer between two flights. MCTs vary by airport and connection type (domestic-to-domestic vs. international-to-domestic) and are guidelines, not guarantees.

Split-ticket itinerary

Two or more flights booked separately, often with different airlines or on different booking platforms. Unlike a single itinerary, airlines have no obligation to accommodate missed connections between split-ticket flights.

Inter-terminal transfer

The process of moving between terminals within the same airport, which may involve shuttles, trains, security re-screening, or outdoor walkways depending on the airport's layout.