Additional Collection/Add-Collect: An additional cost assessed, usually on an airline ticket, to cover an increase in the ticket.

Add-on Fare: Used primarily for international travel, where the fare from a gateway is fixed and a fare for travel to the gateway is added on to provide a total fare for travel.

Advance Purchase Fare: An airfare which requires that the ticket be purchased a minimum period of time prior to departure date.

Airline Designator: 2 or 3-digit alphanumeric code for an air carrier.

Airport Codes: Three-letter codes used to uniquely identify all airports (IATA code).

Airport Tax: A local tax imposed on air tickets and passed along to passengers, used to fund airport maintenance, expansion, and similar expenditures.

Availability: The actual inventory of seats that is really available to be sold at a certain fare. Just because a fare is presented as " available " between two cities does NOT mean seats at that rate are available. This causes much confusion when airfare ads are published, so you must read the " fine print " before calling your agent and asking them to get that fare for you!

Baggage Allowance: The weight or volume of baggage that may be carried by a passenger without additional charge.

Base Fare: The fare, as of an airline ticket, before tax has been added. Commissions are calculated on the base fare.

Blackout Period: Specific dates that a discounted or promotional airfare is not offered.

Booking Code(Class): The alphabetic category in which an airline seat is reserved on a CRS for a specific fare. Also called a fare code (class).

Bumping: The practice of removing a passenger with a confirmed reservation from a full flight. Each airline has its own bumping policy, but generally, the last passengers to check-in and/or arrive at the departure gate are the ones most likely to be bumped.

Cancellation (Charge): A fee assessed for canceling a reservation. For Airline tickets, the cancellation penalty is usually collected by refunding only a portion of the ticket price. For hotel reservations, the cancellation penalty is charged to the credit card or deposit used to secure the reservation.

Capacity-Controlled Fares: A limited number of airplane seats to which a special fare has been assigned. This percentage may change depending upon how quickly seats are selling on the flight.

Category: A specifically defined division in a classification system (class). Can apply to cruise ship cabins, rail accommodations or airline seating configurations.

Change of equipment: A change of aircraft that occurs without a change in the flight number.

Circle Trip: A routing that involves two or more stopovers, after which the passenger returns to the point of origin.

City Pair: In airline bookings, the departure and arrival cities on an itinerary.

Coach: The "economy" section of an aircraft, which may have multiple fares for the same flight

Code Sharing: An agreement whereby airlines permit the use of their CRS code in the flight schedule displays of other airlines.

Commuter Affiliate: A commuter airline that is affiliated with a major airline. Some commuter airlines are owned by their affiliated major airline.

Computerized Reservation System(CRS): Any of several proprietary computer systems allowing real-time access to airline fares, schedules, and seating availability and offering the capability of booking reservations and generating tickets.

Conditional Fare: A fare that guarantees passage on the next available flight if the flight for which the ticket was purchased is full.

Connecting Flight: A flight that requires a passenger to change from one plane to another.

Connection: A stop on a journey that requires a change of planes or other mode of transportation.

Denied Boarding Compensation: Payment and/or voucher given by the airline to those bumped from a flight; may be somewhat negotiable...always ask! See "bumping"

Direct Flight: A flight which requires no change of plane from departure to destination, though the plane may make intermediate stops.

Double Booking/Duplicate Booking: Two reservations for the same traveler on the same day or on overlapping dates. Airlines will cancel both reservations if they discover a duplicate booking.

Electronic Ticket: A "paperless" airline ticket allowing one to check in and fly with just proper photo ID. What may look like a ticket is actually just a paper passenger receipt. E-tickets cannot be lost, or used by anyone else, so they are safer than standard paper tickets, which may soon become extinct.

Fare Basis(Code): The sometimes-confusing code or codes on which the price of an airline ticket is based. Some itineraries contain many different codes. Most will indicate whether a fare is refundable or not. If even one fare code contained in a ticket is nonrefundable, then the entire ticket becomes nonrefundable. Even some first class fares are now nonrefundable!

Gateway City: A city that operates as an arrival or departure point for international flights

Hub: An airport or city in which an airline has a major presence and many flights to other destinations. As an example, Delta has a hub in Atlanta. Many carriers use the hub and spoke system to maximize profits by keeping the aircraft in the air as much as possible. Flights to the hub are many, and from there flights to many other destinations are scheduled

Interline Connection: A flight on one airline that connects to a flight on another carrier - these tickets are usually more expensive than flying all on one carrier but may be the only way to get to a destination in some cases. Also unless an interline agreement for baggage handling exists, you may have to claim your luggage from the first flight and recheck it on the next carrier's flight. Not the best way to travel by air!

Layover: A period of time spent during a trip, sometimes overnight, while waiting for a transportation connection - usually a change of planes

Leg: One segment of a journey, normally referring to an air itinerary, such as the "outbound leg" or the "return leg".

Lowest Available Fare: The current, lowest airfare available for purchase right then - may or may not change within minutes/hours/days!!

Lowest Fare: The lowest published airfare between two cities; airlines may NOT have seats available at that fare, as the airlines usually have a limited number of those seats on any given flight

Maximum Stay: The maximum time you may stay at your destination in order to qualify for a specific airfare. Normally most fares have a 30-day limit, but some are less. Usually, the longer you stay, the higher the fare will be

Minimum Connecting Time: The standard amount of time needed to make a connecting flight in a particular airport. This standard is determined by the air traffic conferences and varies according to the airport and the airline.

Non-Endorsable: A ticket, which is not valid for travel on another carrier.

Non-Refundable: A ticket, which cannot be returned for cash or credit if unused, but may be changeable for a fee.

Non-Stop Flight: A flight which flies directly to your destination with no stops between.

Non-Transferable: A ticket issued in a particular name that cannot be used by another passenger.

No-Show: A traveler who does not appear for a flight on which he or she has a reservation and fails to cancel that reservation properly. Airlines will cancel all further flights on a traveler's itinerary if a reservation is not cancelled.

Offline Connection: A change of aircraft also involving a change of carriers.

Off-Peak: A time when less travel occurs. Fares are usually lower during these times.

Open-Ticket: A ticket valid for a travel between specified points without a reservation or a specific flight number.

Overbooking: The practices of selling more airline seats than are available on a specific flight, to make up for no shows. Requires passengers to be " bumped "...not always voluntarily. To some extent, happens in the hotel industry as well.

Passenger Facility Charge(PFC): A fee for the use of many airports, added in to the cost of an air ticket - another name for an additional tax on travelers.

Passenger Name Record(PNR): The official name of one's reservation in a computer reservation system (CRS).

Penalty Fare: A fare, which carries a penalty for any changes or cancellations once the ticket has been issued. Penalties can range from a dollar amount to a percentage of the ticket's value to the total loss of the value of the ticket.

Point To Point: Refers to the fares between two cities; the service between two cities without additional segments or any continuation.

Promotional Fare: An airfare introduced to increase an airlines market share or to promote service to a particular destination.

Published Fare: An airfare that is listed in the carrier's tariff.

Record Locator: The number assigned to one's reservation in an airline's computer system - can be important to know when there's trouble!

Reissue: The generation of a new ticket that is exchanged for another, due to a change of plans, dates, flights, etc. May involve additional fare, penalties and fees.

Restricted To Airport Check-In: Aircraft seat assignments and boarding passes, which can only be secured at time of airport check-in.

Revalidation: A sticker applied to a ticket indicating a change of date and/or flight number but retention of the original routing.

Saturday Night Stay: The airline requirement that you must stay over a Saturday night during a trip in order to obtain the lowest fare. Usually, there is also an advance purchase requirement as well as other rules that apply, such as travel being limited to certain days of the week, etc.

Segment: A "leg" or part of a journey, usually in reference to an air itinerary. One take off and landing during air travel constitutes a "segment".

Standby: A traveler who does not have a confirmed reservation and must wait at the airline gate for a seat to become available.

Stopover: An international intermediate stopping-point on a journey.

Ticket Issuance: Actual purchase of ticket for flights previously reserved.

Unrestricted Fare: An airfare that has no special advance purchase, Saturday stay or certain days to travel requirements, and is usually refundable. Many full coach and most first class fares are unrestricted.