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All industry have their internal codes, but airlines and airports go to extremes – with many terms making no sense in actual English. “Nonstop” flights stop once, at their destination; “short-shipped” baggage isn’t shipped at all, but left behind at its point of origin.
These terms look designed to baffle passengers. But knowledge is power …
AAA: the three-letter airport code for Anaa airport in French Polynesia, as awarded by Iata (see below). These codes continue up to and including ZZV – Zanesville Municipal airport in Ohio. The theoretical maximum number of codes is 17,576.
Many airports are known primarily by their codes, for example CDG in Paris and JFK in New York – named for 20th-century leaders Charles de Gaulle and John Fitzgerald Kennedy respectively.
Codes are awarded to other locations that are not actual airports. London Paddington station is QQP, because of its status as one end of the Heathrow Express. Some metropolitan areas are also given codes – LON for London, NYC for New York, TYO for Tokyo … – which makes it easier to find the full range of flights to a particular city.
Airlines sometimes apply their own codes to non-airports; for example, Air France no longer flies from Paris to Strasbourg (SXB) due to the high-speed rail connection from CDG, but sells train tickets to the Alsatian city’s railway station, calling it XWG.
A/C: aircraft
Ad-hoc charter: hiring an A/C to cover a gap in a fleet – for example, caused by problems with Rolls-Royce Trent engines fitted to Boeing 787s. The providers are generally airlines that offer no scheduled services, so you can’t ever book with them.
Wamos and Hi-Fly are among the long-haul providers of ad-hoc planes. Avia Solutions Group has a range of short-haul brands, including SmartLynx, as used by easyJet.Titan Airways is a well-respected UK provider that operates regular charter flights for a range of tour operators, as well as providing extra capacity for airlines.
See also damp/dry/wet leasing.
AGP: airport code for Malaga, one of the most popular destinations for British travellers. It is an example of how weird some of these codes are. Malaga airport acquired AGP either because it was to honour the Roman empress Agrippina or because all the obvious codes (MAL, MAG, MGA …) had already gone. Take your pick.
Aisle lice: passengers who stand up as soon as the seat-belt light goes off (or sometimes before), and try to push towards the door – even though it is still closed.
AOG: Aircraft On Ground. The A/C is broken and won’t be going anywhere in a hurry.
APD: Air Passenger Duty, the tax of at least £7 payable by anyone aged two or above on a flight from a UK airport. Most passengers pay £13 for domestic and European flights in economy class.
Long-haul flights in economy covering between 2,001 and 5,500 miles cost £88 in APD, with £92 for 5,501 and over. These will increase by £2 in April 2025.
At the same time the long-haul rate for passengers in anything other than economy class rises from £194 to £216; and the ultra-long-haul rate from £202 to £224.
Arrival time: according to the EU, the time at which the flight reaches the gate and at least one of the doors is open. This is the definition used for the purposes of claiming compensation. Cash payouts are due on flights on UK and EU airlines, and all departures from British and European airports, which arrive three hours or more behind schedule – unless the carrier can demonstrate “extraordinary circumstances” were responsible.
Bumping: denying boarding to passengers with confirmed reservations who turn up on time for the flight on which they are booked. This typically happens when an airline has sold more seats for a flight than there are on the aircraft, on the basis that some passengers will almost certainly fail to show up in time.
In many locations, including the UK, the European Union and the US, passengers are entitled to compensation for overbooking.
Carrier Imposed Charge: nothing to do with governments or airports, but a fee that British Airways, Virgin Atlantic and other airlines apply to try to make extra cash. Its origins lie with the sharply rising cost of fuel in the early years of the 21st century. Airlines imposed fuel surcharges as a way of saying, basically: “We’ve put our fares up but it’s not our fault.”
However, there was a second, more significant effect: anyone redeeming frequent flyer points had to pay the surcharge, which devalued their points and increased airline earnings. Even when fuel prices subsided, carriers kept these surcharges in place.
Check-in chicken: checking in for a budget airline flight as late as possible, in the hope that you will get a better seat. The only time I ever sat in 1A on a Ryanair plane was when I checked in just over two hours ahead, a few minutes before the cut-off.
Civil Aviation Authority (CAA): the UK regulator for air travel.
Cabotage: the right of a foreign airline to fly passengers domestically, eg Wizz Air and Ryanair linking Sicily with mainland Italy and Aer Lingus Regional connecting Belfast City with many airports in Great Britain.
Canx: cancelled, usually referring to a flight.
Chapter 11: also known, disparagingly, as the “carwash”. A form of bankruptcy previously popular among US airlines which provides a company with protection against creditors while at the same time allowing it to continue to trade. Airlines renegotiate with workers and suppliers to reduce the cost base. Spirit Airlines and Silver Airways are currently in Chapter 11.
Classes: the first and most obvious meaning is the division of an aircraft into different cabins. While many low-cost airlines are one-class only, on many BA long-haul flights there are four passenger classes: World Traveller (economy), World Traveller Plus (premium economy), Club World (business class) and First. The generally accepted letters to describe these are Y, W, J and F.
Less obviously, individual cabins are divided into classes for the purposes of selling. For example, “economy light” on Virgin Atlantic is classed as T.
Codesharing: an arrangement that allows airlines to apply their own two-letter IATA carrier code (eg AF for Air France, BA for British Airways, VS for Virgin Atlantic) to another airline’s flight. In reality it is the aircraft that is shared, not the code.
This enables airlines to boast of a wider route network, and offer more flight possibilities, than they could otherwise do.
British Airways has codeshare agreements with a wide range of airlines, including Aer Lingus, airBaltic, American Airlines, Bangkok Airways, China Southern, Fiji Airways, Finnair, Iberia, Japan Airlines, jetBlue, Kenya Airways, Loganair, Qatar Airways, Vistara and Vueling. BA says codesharing “provides a simple, convenient and transparent service that increases customer choice”.
Damp lease: one of three forms of leasing to cover operations, usually longer term than ad-hoc charters. With a damp lease, you rent the plane and the pilots, and supply your own cabin crew.
A wet lease means the cabin crew comes too; it its also known as ACMI, short for “aircraft, crew, maintenance and insurance”. During a British Airways strike in 2010, BA wet-leased capacity from Ryanair.
Dry leasing means you simply rent the plane (like car hire) and supply your own personnel. Example: for a time, Ryanair dry-leased planes from Air Arabia in the summer, when demand for flights in the Gulf was low but between the UK and Spain was high.
Direct flight: you travel in the same plane to your destination but do not necessarily go nonstop. From Heathrow, BA’s and Qantas’s daily departures to Sydney (via Singapore) and Eva Air to Taipei (via Bangkok) are examples of direct flights that stop along the way.
Etops: Extended Twin-engine Operations over water, the concession that allows a plane with two engines to take a route that is more than an hour’s flying time (with only one engine working) from a suitable diversion airport. This allows aircraft to fly straighter, quicker and cheaper courses.
The longest Etops allowance is 370 minutes (six hours, 10 minutes), approved for the Airbus A350 powered by Rolls-Royce Trent XWB engines. The only part of the planet from which suitably equipped aircraft are excluded is a small patch of Antactica.
EU261 (or, more correctly, EC261): the European air passengers’ rights rules which specify obligations for airlines in the event of cancellations, overbooking and long delays. The regulations apply to all flights from EU airports, and flights from airports outside Europe that are operated by EU carriers.
The rules are split into a duty of care which is obligatory regardless of the cause, and cash compensation of between €250 and €600 when the airline has caused the problem. After Brexit, the UK created its own UK261. This is a copy-and-paste of the European law but with cash payouts converted to sterling – ranging from £220 to £520.
Extraordinary circumstances: the only excuse for not paying compensation under EU261– typically bad weather, air-traffic control restrictions or security issues.
Fifth-freedom: the right, under the 1944 Chicago Convention on international air travel, for an airline to fly between two points, neither of which is in its home country. A good example is Air Canada between London Heathrow and Delhi, a continuation of the flight from Calgary. Typically fifth-freedom flights offer lower fares and/or higher standards. Booking a day ahead, direct with the airline, Air Canada is selling London-Delhi for £748 one way in premium economy. British Airways is charging almost four times as much for the same cabin class.
All airlines from EU member states enjoy automatic fifth-freedom rights within the Union, such as Ryanair (of Ireland) flying from Manchester to Naples; easyJet Europe (of Austria) connecting Amsterdam and Barcelona; and Wizz Air (of Hungary) linking Rome and Sofia.
FIM: flight interruption manifest, for when things go Tango Uniform and a flight is cancelled. It is a document that provides a replacement departure on a different airline. It was originally a paper voucher; even though paper tickets disappeared around 15 years ago, the term has remained in use to indicate a passenger being switched to another carrier.
FOP: form of payment. Credit card provides the maximum protection; cash the least.
Gate lice: pushy passengers who bug airline staff by breaking boarding group protocol, usually in a bid to stash their cabin baggage in overhead lockers ahead of other travellers.
GDS: global distribution system. Amadeus, Sabre and Travelport are the market leaders. They provide the interface between individual airlines’ reservations systems and travel agents. Besides flights, they also handle car rental and accommodation.
Grandfather rights: : at slot-constrained airports, of which Heathrow and Gatwick are the most extreme examples worldwide, this means the entitlement to continue to fly to and from a particular airport at specified times.
Slots are held under a use-it-or-lose-it basis; if an airline fails to use a large majority of them, the slots are taken back and offered to other carriers.
HAG: have a go. A term used by check-in staff for a passenger who arrives after the check-in deadline but is permitted to try to get to the gate in time to catch the plane. This is only ever possible with hand baggage, and these days such a courtesy is extremely rare.
But in the past I have been allowed to “have a go” twice by British Airways ground staff in fairly extreme cases: from Gatwick to Naples, when the trains failed and I arrived at the check-in desk 17 minutes before departure; and at New York JFK, when I turned up 28 minutes before departure to Heathrow. On both occasions I made the flight.
Heavy: larger aircraft, generally twin-aisle, from the Boeing 787-9 and Airbus A330 to the 747 “Jumbo” and A380 “SuperJumbo”.
Hotac: hotel accommodation, which should be provided during disruption if an overnight stay is necessary.
IATA: International Air Transport Association, the airlines’ trade body. Headquartered in Montreal in order to be close to …
ICAO: International Civil Aviation Organisation, the Montreal-based UN body that regulates global aviation (and strays into areas such as the dimensions and flexibility of passports).
IRROPS: “irregular operations,” such as problems caused by WX (poor weather) or an AOG (aircraft on ground).
LAGs: liquids, aerosols and gels, which cannot be carried in cabin baggage in quantities above 100ml. Term may include foods such as cheese.
Legacy airline: a traditional carrier, such as British Airways, Lufthansa or Qantas, which pre-dates the “no-frills revolution”. They generally have the benefit of a long-established route network, and the slots involved, but the disadvantage of employment arrangements negotiated when airlines were able to get away with charging absurd fares and running inefficient operations.
Load factor: the proportion of seats on an aircraft filled by fare-paying passengers. If 162 out of 180 seats on an Airbus A320 are occupied by people who have paid for the seats (as opposed to airline staff, freeloading journalists etc), then the load factor is 90 per cent.
A generation ago, load factors were typically in the 70-75 per cent range. Today airlines strive for 90-95 per cent. These figures generally include no-shows, which easyJet estimates as 5 per cent on a typical flight.
Locator: the code of six letters and numbers (sometimes seven) that identifies your booking in an airline’s reservations computer, and looks like A1B2C3. Also called a PNR (passenger name record). In an era when paper tickets are thankfully history, keeping a record of the PNR can be very useful. You will probably need it to check in online. And if you don’t have a PNR for an online booking, there’s a chance the purchase hasn’t gone through.
MCT: minimum connecting time. An airline’s or airport’s stipulation of the least time you should leave between your scheduled arrival and the departure of your connecting flight. At Vienna, international connections have an MCT of just 25 minutes. Even at giant Frankfurt the MCT is 45 minutes, whether you are flying internationally or domestically. At Heathrow Terminal 5, MCT is 1 hour 15 minutes. Once multiple terminals get involved, MCTs extend tiresomely. Some connections in Madrid’s absurdly strung-out airport are 2 hours 45 minutes.
If you don’t mind taking a risk, then you can arrange “self-connects” which undercut the MCT – for example booking a flight from Milan Malpensa Terminal 2 which departs in less than the stipulated 90 minutes margin. But if it goes Tango Uniform because of a delay with the first flight, you lose. Not recommended if you have checked baggage.
Network carrier: an airline such as Air France, British Airways or Lufthansa that operates a wide range of flights from one or more hubs (Paris, Heathrow, Frankfurt/Munich) and offers connecting flights on this network. Largely synonymous with legacy carriers.
NDC: New Distribution Capability, the standard developed by IATA to transform communication between airlines and travel agents. The airline industry wants to offer more than simply a seat from A to B, instead offering a more personalised product – possibly with personalised prices – and NDC is the communications protocol that allows this.
Nonstop flight: stops once, at the destination.
No-show: if you fail to reach the check-in desk before the deadline stipulated by the airline, or are not at the boarding gate in time, then you are classed as a no-show. On “legacy” airlines you will typically have the rest of your itinerary cancelled without notice or compensation. On most no-frills fares you lose the money paid for the flight. Theoretically you can apply for a refund for taxes and charges, but the process is sometimes made so difficult or expensive that people rarely bother.
Open jaw: flying out to one airport and back from another. This is a possibility of which many passengers seem unaware. For example on a trip around Australia, the worst solution is to book a return ticket to Sydney, the furthest big city. Far better to, say, book outbound to Sydney and inbound from Perth – to avoid doubling back. Any kind of fly-drive trip, eg San Francisco-Los Angeles, can benefit from an open-jaw ticket, and on many routes there will not be an increase in the fare.
Operational difficulties: meaningless excuse for whatever has gone wrong this time around.
Oversold: overbooked, ie selling more seats for a flight than the number the plane actually holds. Common practice in aviation, because of the large number of no-shows.
Pushback: the moment at which your aircraft begins to be pushed back from the stand by a tug, officially the departure time of the flight. At some smaller airports, such as London City, there may be no need to push back because the aircraft continues the wide turn with which it arrived.
Quad S: an indication on your boarding pass with the abbreviation SSSS which means Secondary Security Screening Selection – an extra layer of security at US airports. Passengers on government watch lists, or who booked very late for a flight, or paid cash, or whose travel history is of interest, may find themselves experiencing extra pat-down searches or searching interviews at the departure gate.
Rawdogging: one TikTok’s latest travel trends, requiring plane passengers to sit silently and screen-free on long-haul stints in the sky. That means no films, music, sleep, snacks or distractions once in the cabin.
Reprotect: transfer to another airline, usually in the event of IRROPS such as a mechanical failure or a scheduling change. Carriers are often reluctant to do this, but the CAA is insisting they do in many cases.
Seat pitch: the distance between the front of one seat and the front of the next, usually measured in inches. On British Airways and Virgin Atlantic flights in economy it is generally 30-31 inches; on some short-haul flights it can be less.
Self-loading cargo: pejorative term for passengers (sometimes also SLF, for “self-loading freight”).
Short-shipped: luggage not shipped at all (ie left behind at the departure airport)
Slot: permission to land and take off from an airport at a specific time. May be used to describe a long-term concept (eg Qantas has slots at Heathrow to operate daily flights to and from Perth and Sydney) or an on-the-day restriction. The captain of a Jet2 flight from Manchester to Malaga may say, “We have a slot to be airborne at 9.47am, so we’ll wait at the gate a little longer.”
Standby: in the latter part of the 20th century, this was the optimum way to find cheap long-haul flights. Airlines sold empty seats shortly before departure for way below the normal prices – eg £100 one-way from London to New York in the days when that sort of fare was unknown – though even once onboard, it was possible to be tapped on the shoulder just before take off and asked to surrender your seat to a full-fare paying executive.
Nowadays, “standby” refers only to prospective passengers who are waitlisted for an apparently fully-booked flight, and are hoping for no-shows.
Tango Uniform: not in great shape, often used in the sense “it’s gone Tango Uniform” to describe a newly bankrupt airline or, less seriously, a missed connection.
Taxes: actual taxes such as Air Passenger Duty, plus a whole range of charges from to the per-passenger handling fee charged by the airport.
Tech stop: landing for the purposes of refuelling and/or changing crew. Passengers do not get on or off the plane.
UTC: Coordinated Universal Time, equivalent to Greenwich Mean Time, by which all airlines’ operations are calibrated. Times on schedules are shown in local time throughout.
VAT: Value Added Tax. Not payable on air fares to, from or within the UK, though many environmental campaigners say it should be, since air travel is not an essential.
Waypoint: specific locations on the surface of the Earth with five-letter names that are used for air navigation. For example, flying over the Isle of Wight towards the London area, pilots typically traverse KATHY, ABSAV and AVANT. There is a finite number of combinations, and some are duplicated. It was a duplicate waypoint that triggered the failure of the Nats air-traffic control computer on August bank holiday 2023.
White tails: aircraft that have been built without a specific customer. Also planes that show no owner on the tail but which are hired in to cover aircraft shortfalls by airlines.
WX: weather; among pilots, “WX” is used for routine forecasts. More widely, if an aviation worker blames “weather”, they mean the kind that disrupts operations. Example: “We’re expecting some weather later in the day which could cause delays”.
XB-1: the jet-set name for Boom Supersonic’s demonstrator aircraft that broke the speed of sound on 28 January 2025 while testing ahead of planned commercial supersonic flight.
Yield: the amount paid by passengers – generally a relative term. Many transatlantic flights between London and New York are very high yield, while services from the UK to destinations such as Southeast Asia and Australia tend to be low yield.
YYZ: Toronto airport code. Unlike every other country in the world, almost every airport in Canada has a three-letter code beginning with the same letter, Y. Montreal is YUL, Calgary YYC, Vancouver YVR, etc. It is rumoured that this happened in the 1930s when airport codes changed from two letters to three. At the time, it was customary to put the letter Y ahead of the two-letter code to signify, “Yes, we have a weather station and radio communications”. So Canada stuck the Y on the front of them all.
Z: a quoted time that is in UTC as opposed to local time. For example the final Air Canada YYZ-LHR flight of the night leaves at 2335 local time, which is 0435Z the following day.
ZZZ: the airport code applied where there is no official airport code.
Listen to Simon Calder’s Travel Podcast with writer Natalie Wilson on aviation jargon
