Travel agency and business travel glossary

Each definition is written for the US market, where ARC settles agency ticket sales. For the dates themselves, see the ARC calendar 2026 and the void deadline calculator; for a policy to start from, the free travel policy template.

ACM

An Agency Credit Memo: a memo an airline issues to credit a travel agency, for example for commission the agency was owed or a correction in the agency's favor. It is the opposite of an ADM.

Like an ADM, it is processed through ARC in the United States and through the BSP in most other countries.

Also called: Agency Credit Memo

See also: ADM, ARC, BSP, Commission

ADM

An Agency Debit Memo: a bill an airline issues to a travel agency for money it says the agency owes on a ticket, such as a fare or tax collected short, commission claimed above the agreed rate, or a booking practice the airline's rules prohibit.

ADMs can arrive months after travel. Keeping the fare quote, the commission calculation and the reason for any correction makes an ADM much easier to check and, where it is wrong, to dispute.

Also called: Agency Debit Memo, debit memo

See also: ACM, Debit memo dispute, Commission, ARC, BSP

In TripDesk365: TripDesk365 never overwrites the commission it first calculated for a ticket: a later correction is stored beside it, with the reason and who made it.

APIS

The Advance Passenger Information System: the US Customs and Border Protection system through which airlines send passenger and crew details, such as full name, date of birth, gender, nationality and travel-document details, for international flights to and from the United States.

Many other countries run similar advance passenger information schemes. Agencies often add the data to the booking ahead of time (in the GDS, as a DOCS entry) so the traveller has less to do at check-in.

Also called: Advance Passenger Information System, API data

See also: Secure Flight, PNR

ARC

The Airlines Reporting Corporation: the airline-owned company that accredits US travel agencies to sell airline tickets and settles the money between those agencies and the airlines. Agencies report their ticket sales to ARC each week, and ARC collects what is owed and pays the airlines.

ARC does in the United States roughly what IATA's BSP does in most other countries. Its weekly calendar, its holidays and its deadlines set the rhythm of an agency's week.

Also called: Airlines Reporting Corporation

See also: ARC accreditation, Weekly sales report, PED, IAR, BSP

In TripDesk365: TripDesk365 holds ARC's published 2026 holiday calendar and applies it to void deadlines and to the weekly sales-report deadlines.

ARC accreditation

Approval by ARC that allows an agency location to issue tickets on the airlines that settle through ARC and to report those sales through ARC. Each accredited location has its own ARC number.

ARC sets requirements an agency must meet to obtain and keep accreditation, and offers more than one type of it. Agencies without accreditation often sell air through a host agency or a consolidator instead.

See also: ARC, Host agency, Consolidator, IATAN

Back office

The accounting side of a travel agency or TMC: invoicing clients, recording what was sold and what is owed to suppliers, reconciling with ARC or the BSP, tracking commission and paying agents.

In the agency world the term usually means the system that holds these records, fed from the bookings made in a GDS or an online booking tool.

See also: Mid office, TMC, Commission, Weekly sales report

In TripDesk365: TripDesk365's back office covers client invoices, credit and debit notes, commission on each booking and agent payouts.

Base fare

The airline's price for the journey itself, before taxes, fees and carrier-imposed surcharges are added. It is set by the fare basis and comes with that fare's rules.

The total a traveller pays is the base fare plus taxes, fees and charges: government taxes, airport and security fees and, on many airlines, a carrier-imposed surcharge (YQ/YR). Airline commission is normally calculated on the base fare, so the share of the total that earns commission can be small.

Also called: fare

See also: YQ/YR carrier surcharges, Fare basis, Commission, Commissionable fare

BSP

The Billing and Settlement Plan: IATA's system for settling ticket sales between accredited travel agencies and airlines, used in most countries outside the United States. Agencies report sales and pay through the BSP for their market, and the BSP pays the airlines.

Each country or region has its own BSP with its own reporting and payment calendar. In the United States the same job is done by ARC.

Also called: Billing and Settlement Plan, IATA BSP

See also: IATA, ARC, ADM, ACM

CO₂e

Carbon dioxide equivalent: a way of expressing the warming effect of several greenhouse gases as the amount of carbon dioxide that would have the same effect. For a flight it is reported per passenger, and it is always an estimate.

Methods differ in the aircraft and load they assume, in how they share a flight's emissions between cabins, and in whether they include non-CO₂ effects (see radiative forcing), so figures from different calculators are not directly comparable.

Also called: CO2e, carbon dioxide equivalent

See also: Radiative forcing, Travel policy

In TripDesk365: TripDesk365 estimates CO₂e per traveller for every itinerary with the UK government's (DESNZ) 2025 conversion factors, and totals it per client for a chosen period.

Codeshare

An arrangement under which an airline sells seats under its own flight number on a flight operated by another airline. The marketing carrier sells the ticket; the operating carrier flies the aircraft.

Travellers usually check in with the operating carrier and use its terminal, so an itinerary should say who operates each flight.

See also: Interline

Commission

The amount an airline or other supplier pays an agency for selling its product, usually a percentage of the base fare. Rates are set by the supplier, often vary by route, cabin and booking class, and many fares pay none.

On an ARC ticket the commission is entered when the ticket is issued and reported in the weekly sales report. Commission claimed above what the airline agreed can come back as an ADM.

See also: Commissionable fare, Override, Net fare, ADM, RBD (booking class)

In TripDesk365: TripDesk365 calculates commission for each direction of travel, as airline contracts state it, and keeps the original figure beside any later correction.

Commissionable fare

A fare on which the airline pays the selling agency a commission, normally a percentage of the base fare. The agency's income on it is that commission, plus any service fee it charges the client.

Also called: published fare

See also: Commission, Net fare, Service fee, Base fare

Consolidator

A wholesaler that holds contracts with airlines for discounted, usually net, fares and sells tickets on them to travel agencies, which add their own markup or fee.

Consolidators usually issue the tickets themselves, under their own accreditation, so an agency without ARC accreditation can still sell those fares.

See also: Net fare, Markup, Host agency, ARC accreditation

Cost centre

The department, project or budget a business trip is charged to, recorded on the booking so travel spend can be reported and recharged correctly.

Also called: cost center

See also: Travel policy, Pre-trip approval, Back office

In TripDesk365: In TripDesk365 a corporate client's bookings can carry a cost centre, and fields such as a project code can be made required before a trip is ticketed.

Debit memo dispute

An agency's formal challenge to an ADM it believes is wrong, made within the time the airline allows and backed by evidence such as the fare quote, the fare rules or the commission agreement.

In the United States, ADMs processed through ARC are reviewed and disputed in ARC's Memo Manager. An ADM that is not disputed in time is normally collected through the agency's settlement.

Also called: ADM dispute

See also: ADM, ACM, ARC, Weekly sales report

Duty of care

An employer's responsibility to take reasonable steps to protect the health, safety and security of employees while they travel for work. It is both a legal and a moral responsibility, and what the law requires varies by country and state.

In practice it means knowing where travellers are, warning them about risks, being able to reach and help them in an emergency, and learning from incidents. This is not legal advice: take advice on what applies to your organization.

See also: Travel policy, Pre-trip approval, TMC

In TripDesk365: TripDesk365 shows the US State Department advisory level for each destination country on a booking, and a map of travellers departing, in the air or just landed, with live positions where flight data has them.

E-ticket

An electronic ticket: the record of a ticket sale held in the validating airline's database rather than on paper, identified by a 13-digit ticket number. The traveller receives an itinerary receipt.

The first three digits of the ticket number are the validating airline's code.

Also called: electronic ticket, ticket number

See also: Ticket coupon, EMD, PNR, Void

In TripDesk365: An e-ticket receipt or an airline email can be imported into TripDesk365 as a draft booking, which a person checks before it is saved.

EMD

An Electronic Miscellaneous Document: the electronic record airlines use to sell services other than the flight itself, such as extra bags, seats, lounge access or change fees, and to hold residual value. It has its own 13-digit number.

An EMD can be associated with a ticket and its flight coupons (EMD-A) or stand alone (EMD-S).

Also called: Electronic Miscellaneous Document

See also: E-ticket, Ticket coupon

Exchange

Replacing an issued ticket with a new one, for example to change dates or routing, using the value of the original ticket towards the new fare. The fare rules decide the change fee, the fare difference and any conditions.

Voluntary changes follow the fare rules. Changes caused by the airline usually follow the airline's own policy instead (see involuntary change).

Also called: reissue

See also: Refund, Void, Involuntary change, Schedule change, Ticket coupon

In TripDesk365: A reissue or date change can be requested from a booking in TripDesk365, and the request goes to the operations team's queue.

Fare basis

The code that identifies the exact fare a ticket was priced with. It usually starts with the booking class letter, followed by letters and numbers the airline uses for conditions such as season, day of week or advance purchase.

The fare rules attached to the fare basis decide refunds, changes and restrictions. Apart from the first letter, codes are airline-specific, so read the rules rather than guessing from the code.

Also called: fare basis code

See also: RBD (booking class), Base fare, PTC

GDS

A Global Distribution System, such as Amadeus, Sabre or Travelport: a network that lets travel agencies search, book and ticket flights, and also hotels, cars and rail, from many suppliers in one place.

A booking made in a GDS lives there as a PNR, and the airline keeps its own copy. Each agency office works in the GDS under its own pseudo city code.

Also called: Global Distribution System

See also: PNR, PCC, NDC, Queue, Record locator

In TripDesk365: A booking can be imported into TripDesk365 by pasting a GDS screen; a person checks the draft before it is saved.

Host agency

An established, accredited agency that lets independent travel advisors sell under its accreditation and supplier agreements, usually in return for a share of the commission or a fee.

The host typically provides booking tools, ticketing and accounting, and pays each advisor their share once the supplier's commission has been received.

See also: ARC accreditation, Consolidator, Commission

IAR

Interactive Agent Reporting: ARC's web application in which an agency reviews its weekly sales, makes allowed corrections and authorizes its sales report for settlement.

Voids and some corrections, such as a change to the commission on a ticket, can be made in IAR while the week is still open. Once the report is authorized, a correction generally needs a memo instead.

Also called: Interactive Agent Reporting

See also: Weekly sales report, PED, ARC, Void, ADM

In TripDesk365: TripDesk365 accepts a commission correction only while that week's sales report is still open; after that it refuses the edit, because the correction then needs a memo.

IATA

The International Air Transport Association: the global trade association of airlines. It sets many industry standards, including airline and airport codes and ticketing and messaging standards, and runs agency accreditation and the BSP in most countries outside the United States.

In the United States, agencies settle through ARC rather than a BSP, and deal with IATAN for IATA's programmes.

Also called: International Air Transport Association

See also: BSP, IATAN, ARC, NDC

IATAN

The International Airlines Travel Agent Network: part of IATA, it endorses US travel agencies, issues their IATA numeric code, and issues ID cards that suppliers recognize as proof that someone is a travel professional.

IATAN endorsement does not on its own let an agency issue airline tickets in the United States; that needs ARC accreditation or a host or consolidator that has it.

Also called: International Airlines Travel Agent Network

See also: IATA, ARC accreditation, Host agency

Interline

An agreement between airlines to accept each other's tickets and carry each other's passengers, so a single ticket can include flights on more than one airline.

Without an interline agreement, flights on two airlines need separate tickets, and the first airline is not responsible if a delay makes the traveller miss the second flight.

Also called: interline agreement

See also: Codeshare, E-ticket, Married segments

Involuntary change

A change to a ticket that the traveller did not ask for, caused by the airline: a cancellation, a significant schedule change, a missed connection or a downgrade. The airline's own policy then decides what the traveller is entitled to, rather than the fare's change rules.

Usual options are rebooking without a change fee and, for a cancellation or a significant change, a refund even on a non-refundable fare. The details differ by airline and by country.

Also called: involuntary reissue

See also: Schedule change, Exchange, Refund, Queue

Known Traveler Number

The number that identifies a member of a US trusted traveler program, such as TSA PreCheck, Global Entry, NEXUS or SENTRI. Added to a reservation with the traveller's exact name and date of birth, it makes them eligible for TSA PreCheck screening on participating airlines.

Eligibility is decided flight by flight, so a KTN on the booking does not guarantee PreCheck.

Also called: KTN

See also: Secure Flight, Redress number, PNR

Markup

An amount an agency adds to a net fare, or to another cost, to set the price it sells at. On a net fare, the markup and any service fee are the agency's income.

Unlike a service fee, a markup is built into the price the client sees rather than shown as its own line.

See also: Net fare, Consolidator, Service fee

Married segments

Two or more connecting flights that an airline sells together as one unit, because the seats were available for the connection as a whole. They cannot be changed or cancelled one at a time without losing that availability or the fare.

Splitting or rebooking one leg of a married connection separately can lose the space that made the fare possible, and airlines can treat attempts to get round married-segment control as a prohibited booking practice.

Also called: married connection

See also: RBD (booking class), PNR, ADM

Mid office

The systems and work between booking and accounting: checking bookings for quality and policy, applying fees, working queues, and preparing data for invoicing and reporting.

See also: Back office, Queue, TMC

NDC

New Distribution Capability: an IATA standard for the messages airlines use to send offers, including fares, bundles and extras, to travel agencies and other sellers. NDC content can reach an agency directly from the airline, through an aggregator or through a GDS.

An NDC booking may not be changed or refunded with the same steps as a traditional GDS booking, so check how each airline's NDC content is serviced.

Also called: New Distribution Capability

See also: GDS, IATA, EMD

Net fare

A fare an airline negotiates with an agency or consolidator at a confidential price, without commission. The seller adds its own markup or service fee to set the selling price.

Net fares are private, and the airline's contract usually limits who may sell them and how they may be shown.

Also called: private fare, negotiated fare

See also: Markup, Consolidator, Commissionable fare, Service fee

OBT

An online booking tool: a self-service website or app where employees book business travel within their company's travel policy, usually backed by a TMC that issues and services the bookings.

Also called: online booking tool, self-booking tool

See also: TMC, Travel policy, Pre-trip approval

Open jaw

A trip in which the traveller flies home from a different city from the one they flew into, or returns to a different city from the one they left. For example: New York to London, then Paris back to New York.

Whether an open jaw can be priced as one round-trip fare depends on the fare rules.

See also: Stopover, Fare basis

Override

An extra commission or incentive an airline pays an agency or consolidator on top of standard commission, usually for reaching sales or market-share targets set in a contract.

Some overrides are paid on each ticket and some after the end of a contract period, based on results, so they are often tracked separately from the commission on each ticket.

Also called: override commission, incentive

See also: Commission, Consolidator

PCC

A pseudo city code: the code that identifies an agency's office in a GDS. Bookings, queues, fares and ticketing permissions belong to a PCC.

Sabre and Travelport call it a PCC; Amadeus calls it an office ID. An agency can have several, for example one per location or per point of sale.

Also called: pseudo city code, office ID

See also: GDS, Queue, PNR

PED

Period ending date: the last day of an ARC reporting week. ARC weeks run Monday to Sunday, so the PED is the Sunday, and it identifies the week a sale was reported in.

The week's sales report is due on the Tuesday after the PED. ARC publishes the dates, and they move around ARC holidays.

Also called: period ending date

See also: Weekly sales report, IAR, ARC

In TripDesk365: TripDesk365 files each ticket into its ARC week when it is issued, with that week's report deadline adjusted for ARC holidays.

PNR

A passenger name record: the reservation record in a GDS or airline system that holds a booking's travellers, flights, contact details, ticketing arrangement and remarks. It is identified by a record locator.

A PNR is not a ticket. A booking can exist with no ticket issued, and each ticket is a separate record linked to it.

Also called: passenger name record, booking

See also: Record locator, GDS, E-ticket, Ticketing time limit, Queue

Pre-trip approval

A step in which a manager or travel manager approves a business trip, or a trip that breaks travel policy, before the ticket is issued and the money is spent.

Approving while the fare is held, rather than after ticketing, avoids paying for a ticket that is then refused.

Also called: travel approval

See also: Travel policy, Cost centre, Ticketing time limit, OBT

In TripDesk365: In TripDesk365 a booking that breaks a blocking policy rule cannot be ticketed until a second person approves it, and the person who asked cannot approve their own booking.

PTC

A passenger type code: the three-letter code that tells the airline what kind of passenger a fare is for, such as ADT (adult), CHD (child), INF (infant without a seat) or SRC (senior). Fares, discounts and rules can differ by passenger type.

Also called: passenger type code

See also: Fare basis, PNR

In TripDesk365: TripDesk365 records each traveller's passenger type, and an agency's rules can refuse a type it may not sell before the fare is held.

Queue

A work list in a GDS where bookings are placed, automatically or by hand, for someone to act on: schedule changes, ticketing deadlines, waitlist clearances, airline messages or tasks passed between colleagues. Each queue belongs to an office (PCC).

Working queues every day is how an agency catches airline changes before the traveller does.

Also called: GDS queue

See also: PCC, GDS, Schedule change, Ticketing time limit, Mid office

Radiative forcing

A measure of how much something changes the balance of energy in the atmosphere. In flight-emissions reporting, a figure "with radiative forcing" also counts the non-CO₂ warming effects of flying at altitude, such as contrails, nitrogen oxides and water vapour.

The size of these effects is scientifically uncertain, so methods differ. The UK government's (DESNZ) business-travel factors are published both with and without them.

Also called: RF, non-CO2 effects

See also: CO₂e

In TripDesk365: TripDesk365's CO₂e figures include radiative forcing, and the figure without it is kept alongside.

RBD (booking class)

A reservation booking designator: the one-letter code for the inventory a seat is sold from, such as Y, B or M in economy or J and C in business. The RBD links the seat to a fare and its rules.

Each airline chooses its own letters, so the same letter can mean a different cabin or fare on another airline. Commission contracts are often written by RBD.

Also called: reservation booking designator, booking class, class of service

See also: Fare basis, Married segments, Waitlist, Commission

In TripDesk365: Commission contracts in TripDesk365 can set a different rate for each booking class, as airline contracts often do.

Record locator

The six-character code that identifies a booking (PNR) in a GDS or airline system, such as ABC123. The GDS and each airline on the booking may each have their own locator for the same trip.

Also called: confirmation code, booking reference, PNR locator

See also: PNR, GDS

In TripDesk365: TripDesk365 will not import a booking whose record locator is already on file for the agency.

Redress number

A number the US Department of Homeland Security issues through its Traveler Redress Inquiry Program (DHS TRIP) to a traveller who has applied after screening difficulties, such as being mistaken for someone on a watch list. Added to a reservation, it helps match the traveller correctly.

Also called: DHS TRIP redress control number

See also: Secure Flight, Known Traveler Number

Refund

Returning the unused value of a ticket to the original form of payment, less any penalty the fare rules impose. A non-refundable fare may return only some taxes, or nothing, unless the airline cancels or significantly changes the flight.

Refunds of ARC tickets are reported in the weekly sales report, and the commission on the refunded value normally goes back to the airline.

See also: Void, Exchange, Involuntary change, Weekly sales report

In TripDesk365: A refund can be requested from a booking in TripDesk365, and the request goes to the operations team's queue.

Schedule change

A change the airline makes to a booked flight's times, flight number, routing or aircraft after the booking was made. The agency is usually told through a GDS queue and must accept the change or rebook the traveller.

A small change is usually just accepted. A larger one can break a connection or entitle the traveller to rebook or to a refund under the airline's policy (see involuntary change).

See also: Involuntary change, Queue, Exchange

Secure Flight

The US Transportation Security Administration (TSA) programme that screens airline passengers against watch lists. For covered flights within, to, from and over the United States, airlines must collect each passenger's full name as it appears on their ID, date of birth and gender, and pass on a Redress number or Known Traveler Number where the passenger has one.

A name that does not match the traveller's ID is one of the most common causes of trouble at the airport, so agencies collect these details exactly.

See also: APIS, Known Traveler Number, Redress number, PNR

In TripDesk365: TripDesk365 will not ticket a booking until each traveller's date of birth and gender are recorded.

Service fee

A fee the agency charges its client for its own service, separate from the airline fare, such as a booking, ticketing or change fee. It is the agency's income and is usually invoiced as its own line.

See also: Markup, Net fare, Commissionable fare, Back office

Stopover

A deliberate stop at an intermediate point on a journey, longer than a connection. On international itineraries this generally means more than 24 hours, and on US domestic itineraries more than 4 hours.

Whether a stopover is allowed, and at what charge, depends on the fare rules.

See also: Open jaw, Fare basis

Ticket coupon

One flight on a ticket. An e-ticket has a coupon for each flight, and each coupon has its own status, such as open for use, used, exchanged or refunded.

Coupon status shows what can still be done with a ticket: a used coupon cannot be refunded or exchanged.

Also called: flight coupon

See also: E-ticket, EMD, Void, Exchange, Refund

Ticketing time limit

The deadline by which a held booking must be ticketed, set by the airline or the fare rules. If it passes without a ticket, the airline can cancel the seats and the fare may no longer be available.

Airlines often send the deadline to the booking or to the agency's queue, and it can be earlier than the fare's advance-purchase rule.

Also called: TTL, ticketing deadline

See also: PNR, Queue, Pre-trip approval

In TripDesk365: TripDesk365 will not ticket a booking once the airline's ticketing deadline on it has passed.

TMC

A travel management company: an agency that manages business travel for companies, typically providing booking by agents and an online booking tool, policy support, duty of care, round-the-clock service and reporting under a service agreement.

Also called: travel management company

See also: OBT, Travel policy, Duty of care, Mid office, Back office

Travel policy

A company's written rules for business travel: who may travel, how to book, which cabins, fares and hotels are allowed, what needs approval, what is reimbursed, and how travellers are looked after.

A policy that is short and specific is easier to follow, and easier for a booking tool to check.

Also called: corporate travel policy

See also: Pre-trip approval, Duty of care, OBT, Cost centre

In TripDesk365: In TripDesk365 a corporate travel policy is a set of rules, and every rule a fare breaks is listed together, not just the first.

Void

Cancelling a ticket shortly after it was issued, so the sale is removed as if it had not happened, normally with no penalty. Once the void window has closed, the ticket can only be refunded or exchanged under its fare rules.

A ticket can generally be voided only if none of its coupons has been used or exchanged. Voiding the ticket does not by itself cancel the flights in the booking.

See also: Void window, Refund, Exchange, IAR, Ticket coupon

Void window

The time after issue during which a ticket can still be voided. For a sale reported through ARC and issued through a GDS, it generally runs until 11:59 p.m. Eastern Time on the next business day after issue, and ARC extends it when that day is an ARC holiday.

An airline can apply stricter rules to its own tickets, and voiding late is a common cause of debit memos, so many agencies work to an earlier cut-off of their own.

See also: Void, IAR, ARC, ADM

In TripDesk365: TripDesk365 works out each ticket's void deadline in US Eastern Time from its issue date, skipping weekends and ARC holidays.

Waitlist

A list an airline keeps of passengers who want a flight or booking class that is full. If seats become available, waitlisted passengers may be confirmed, usually in a priority order the airline sets.

A waitlisted flight is not a confirmed seat, so travellers should hold a confirmed alternative until it clears.

See also: RBD (booking class), Queue, PNR

Weekly sales report

The report an ARC-accredited agency submits for each reporting week, listing its ticket sales, refunds, exchanges and other transactions. It is reviewed and authorized in IAR, and ARC then settles the money between the agency and the airlines.

ARC's standard is that the report must be authorized by 1:59 p.m. Eastern Time on the Tuesday after the period ending date. ARC publishes different dates, and sometimes times, for weeks around its holidays.

Also called: ARC sales report, ARC report

See also: IAR, PED, ARC, Void, ADM

In TripDesk365: TripDesk365 tracks each ARC week and its report deadline, adjusted for ARC holidays.

YQ/YR carrier surcharges

Charges an airline adds to a ticket under the codes YQ and YR, for example for fuel or insurance. They are collected alongside the taxes but are set by the airline, not by a government.

They can be a large part of the total on some international routes. Whether they earn commission depends on the airline's terms, and in many markets they do not.

Also called: carrier-imposed fees, fuel surcharge

See also: Base fare, Commission, Commissionable fare

In TripDesk365: Each commission rule in TripDesk365 states whether it pays on the base fare alone or on the base fare plus carrier surcharges.