Work backwards from your flight time: when you should arrive at the airport, and what time you need to leave home. Recommended buffers for international and domestic flights are built in.
A common rule of thumb is to arrive 2–3 hours before an international flight and 1–1.5 hours before a domestic one. Add extra margin during holiday peaks or if you're checking bags.
IATA three-letter codes (ICN, JFK) appear on tickets, baggage tags and bookings. These are the ones travellers see.
ICAO four-letter codes (RKSI, KJFK) are used for air traffic control and flight plans. The first letters encode region, which makes them systematic — K for the continental US, RK for Korea, RJ for Japan.
IATA codes are unique but often not intuitive. Chicago O'Hare is ORD after its former name, Orchard Field; Washington Dulles is IAD because DUL was too easily confused with another airport.
Cities with several airports have a city code covering all of them.
London LON — Heathrow (LHR), Gatwick (LGW), Stansted (STN) and others. New York NYC — JFK, LaGuardia (LGA), Newark (EWR). Seoul SEL — Incheon (ICN) and Gimpo (GMP).
Searching by city code is convenient, but different airports can be one to two hours apart. For any itinerary involving a connection, confirm the specific airport code.
Landing at Heathrow and departing from Gatwick means crossing London — allow four hours minimum.
Domestic — 1 to 1.5 hours. Security queues build at peak times.
International — 2 to 3 hours, and 3 during holiday peaks.
Baggage cut-off is separate and typically closes 60 minutes before departure. Being at the airport does not help if the counter has shut.
Gates close 20 to 30 minutes before departure. The departure time is when the aircraft moves, not when the door closes.
Large airports separate terminals by 15 to 20 minutes of shuttle transit. At Incheon, Korean Air, Delta, Air France and KLM use Terminal 2 while most others use Terminal 1.
Getting it wrong costs 30 to 40 minutes with the wait. Recheck the terminal on your ticket the day before — airlines do move.
Codeshare flights are the usual trap. If you booked with airline A but airline B operates the flight, you need B's terminal.
Transit visas — some countries require paperwork even without leaving the airport. The US requires ESTA or a visa even for transit.
Baggage transfers automatically on a single booking; separate bookings mean collecting and rechecking.
Airport taxes and fuel surcharges vary with routing, so comparing totals rather than base fares shows the real difference.
Airport codes, positions and time zones are bundled with this site rather than fetched, so lookups work offline.
Airport information changes — new airports open, terminals get reassigned, codes change. Confirm with the airline and airport before travelling.
Usually 2–3 hours before departure. During peak season, with checked bags, or at busy hubs, 3 hours is the safe choice.
It varies by airline, but international check-in counters often close 40–60 minutes before departure and gates 10–20 minutes before. Always confirm with your airline.
With no checked bags you can trim some time, but security and immigration queues don't shrink — for international flights, 90 minutes before departure is a sensible minimum.
What this tool bases its numbers on, and how far those numbers go.
Leave time = boarding time − recommended airport buffer − your travel time to the airport. The buffer defaults to the common advice of 2 to 3 hours for international and 1 to 1.5 hours for domestic departures, and the timeline shows each subtraction separately so you can override any step.Boarding at 14:00 with a 3-hour international buffer puts you at the airport by 11:00. With 70 minutes of travel, you leave home at 09:50.