Flight Booking Glossary

Airline and booking sites use a lot of jargon. This glossary explains the terms you're most likely to meet when searching, comparing and booking flights. The definitions describe how things work in general. Specific rules vary by airline and country, so always check the conditions on your own ticket.

Tickets and itineraries

One-way: A single journey from A to B, with no return included.
Round trip (return): An outbound and return journey booked together on one ticket.
Open-jaw: A round trip where you fly into one city and home from another (A to B, then C to A), or fly out to one place but return to a different airport in your home city.
Multi-city: An itinerary with three or more separate flights, such as A to B, B to C, then C to A.
Connecting flight: A journey with one or more stops where you change planes, usually booked as one ticket.
Direct vs. non-stop: A non-stop flight doesn't land anywhere between origin and destination. A direct flight may stop but keeps the same flight number, sometimes with no plane change.
Layover vs. stopover: A layover is a short stop between connecting flights, often a few hours. A stopover is a longer deliberate stay, often more than 24 hours, sometimes offered by an airline at no extra fare.
Codeshare: A flight sold by one airline but operated by another. You book under one flight number but fly on a partner's plane.
Self-transfer: Connecting between two separate tickets. You collect your own bags and re-check in, and the airlines aren't responsible if you miss the second flight.

Fares and prices

Fare class (booking class): A letter code that groups seats by price and conditions within the same cabin. Cheaper classes usually have stricter change and refund rules.
Fare basis: A code on your ticket that identifies the fare rules that apply to it.
Basic economy: A stripped-down fare, often with no free changes, seat selection or checked bags.
Taxes and surcharges: Government and airport charges, and sometimes airline-imposed fuel or carrier charges, added to the base fare.
Ancillary fees: Optional or extra charges for items such as bags, seat selection, meals and priority boarding.
Price alert: A notification from a search site when the fare on a tracked route changes.
Hidden-city ticketing: Booking a flight with a connection and leaving the journey at the stop, skipping the last leg. It usually breaches the airline's conditions. See our risks guide.

Airports and timing

Minimum connection time (MCT): The shortest time an airport allows between flights on a single ticket. Connections shorter than this can't normally be booked.
Terminal: A building within an airport. Connections that involve changing terminals usually need more time.
Airside / landside: Airside is the area beyond security and passport control. Landside is the public area before it.
Check-in cut-off: The deadline before departure after which the airline won't accept you or your bags for the flight.
Secondary airport: A smaller airport serving the same city as a main hub, often used by low-cost carriers. See our secondary airports guide.

Baggage

Personal item: A small bag that fits under the seat in front of you.
Cabin (carry-on) bag: A bag that goes in the overhead locker, subject to size and weight limits that differ by airline.
Checked baggage: Luggage handed over at check-in and carried in the hold.
Interline / through-checking: Bags checked through to your final destination on one ticket, or on separate tickets where airlines have an agreement. Not available with most self-transfers.

Disruption and rights

Denied boarding: When an airline refuses to carry you, for example because the flight is oversold. Compensation rules vary by region.
Conditions of carriage: The airline's legal terms covering your ticket, baggage, changes, refunds and delays.
Rerouting: When an airline moves you to a different flight after a cancellation or major delay.