Twenty airline terms, translated. What each one means, what it is worth, and what to do about it, standing at the gate. Facts reviewed August 2026.
Every term you are likely to hear when a flight falls apart, in plain English, alphabetized. Each entry says what the words mean and what to do with them. Figures come only from US DOT and EU rules. Facts reviewed August 2026.
Owed money right now? The calculator on Know your rights does the math for your exact situation, the disruption playbook gives you the steps, and Fix my trip finds the way home.
A flight sold under one airline's name and flight number but flown by a different airline's plane and crew. When a codeshare breaks, the operating airline handles day-of-travel problems like delays and rebooking, while the airline that sold you the ticket generally handles refunds. Check in and track the flight with the operating carrier's app, whatever your confirmation email says.
The legal terms you accepted when you bought your ticket. Every US airline publishes its contract of carriage on its website, and it defines what that airline owes you for cancellations, delays, misconnects, no-shows, and standby - the specifics genuinely differ between carriers. When any entry on this page says policies vary, the carrier's contract of carriage is where the real answer lives.
A controllable cancellation is one the airline caused - mechanical problems, crew scheduling, its own IT. Uncontrollable means weather or air traffic control. The label decides the extras: under commitments large US airlines have published on the US DOT customer service dashboard, meals after a 3 hour wait and a hotel for an overnight apply to controllable disruptions, and generally not to weather events. The refund for a canceled flight is owed either way, whatever the cause.
Your flight lands at an airport that is not on your ticket, usually for weather, a medical emergency, or a mechanical problem. The airline is responsible for getting you to your ticketed city, whether that is the same plane continuing later, a different flight, or a bus - ask the crew what the plan is, and get into the airline's app before the whole cabin does. What you are owed while you wait depends on the cause, so check the carrier's contract of carriage.
The obligation to look after you while a disruption plays out. Under EU and UK rules it is the law: meals, refreshments, phone access, and a hotel plus transfers if you are stranded overnight, owed even when the cause is weather. The US has no duty of care law - what exists instead are the care commitments large US airlines have published on the US DOT dashboard, and those apply to controllable disruptions only.
The European air passenger rights law. It pays fixed cash compensation per passenger - €250 for flights up to 1,500 km, €400 for medium-haul, €600 for long-haul - when you arrive 3 or more hours late or your flight is canceled on less than 14 days notice, unless the airline proves extraordinary circumstances. It covers flights departing the EU on any airline and flights into the EU on EU carriers; the UK mirror, UK261, pays £220, £350 or £520. The amount does not depend on what your ticket cost, and children on their own ticket count too.
Your plane pushes back, then comes back to the gate before takeoff - a warning light, a sick passenger, a ground stop. A gate return changes nothing by itself: if the flight is later canceled, normal cancellation rights apply, and a long wait on board brings the tarmac delay rule into play. Use the time to look at alternatives in the app before a cancellation is announced to the whole cabin.
A behind-the-scenes agreement that lets one airline rebook you and check your bag through on another airline's flights under a single ticket. It is what makes rebooking onto a different carrier during a meltdown possible at all; many low-cost carriers have no interline agreements, which is why an agent sometimes cannot move you to the airline with the next open seat. A useful question at the counter: which airlines can you interline me to?
You had a confirmed reservation and met the deadlines, and the airline still would not board you - usually an oversold flight without enough volunteers. This is the one US disruption with a legally set cash payment: under US DOT rules, generally 200 percent of your one-way fare up to $1,075 if you arrive 1 to 2 hours late, or 400 percent up to $2,150 if you arrive later than that, depending on the circumstances. It is payable in cash rather than a voucher if you ask, and it is on top of your ticket, which keeps its value. Do not sign anything at the gate before you know this number.
Airline shorthand for irregular operations - the internal label for a stretch when the schedule has broken down, whether from a storm system, an air traffic program, or an IT outage. Hearing it means the disruption is network-wide, not just your flight, so seats on later flights are disappearing while you stand in line. Airlines often publish fee waivers during IROPS that let you rebook flexibly; look for the travel alert page in the app, and work every routing, not just the one you were booked on.
The shortest layover an airport and airline combination officially allows - booking systems will not sell a connection below it. Book a connection at or above MCT on a single ticket and it is protected: if the first flight is late and you misconnect, the airline puts you on its next available flight. Build the same connection out of two separate tickets and that protection disappears entirely. When rebooking during a disruption, longer than MCT is your friend.
Arriving too late to make the next flight on your itinerary. On a single ticket, a misconnect is the airline's problem: it rebooks you on the next available flight at no charge, and if the cause was controllable, the care commitments above can apply on top. On separate tickets, the second airline sees only a no-show and owes you nothing - you are buying a new ticket. One ticket or two decides almost everything, so know which you have before you reach the agent.
The treaty that sets airline liability on most international itineraries - lost, damaged, and delayed bags, and certain damages caused by delay. For baggage it caps what the airline owes at about 1,519 Special Drawing Rights per passenger, an IMF currency unit whose dollar value moves. That is a ceiling, not an automatic payout: you claim the documented value of what was actually lost. US domestic trips fall under US federal rules instead, with a baggage liability cap of about $4,700 per passenger - either way, file the bag report before you leave the airport.
The contract of carriage clause that lets an airline cancel the rest of your itinerary if you skip a flight on it without notice - miss the outbound, and the return can vanish with it. The specifics vary by airline and fare, so check the carrier's contract of carriage before deliberately dropping a leg. If a disruption will make you miss a segment, tell the airline before departure; that call is usually what keeps the rest of the ticket alive.
The fork in the road after a cancellation or significant delay. Accept the airline's replacement flight and travel, and no refund is owed - you flew. Decline it, and under US DOT rules you are owed a full cash refund of the unused ticket to your original payment method - due within 7 business days for card purchases and 20 calendar days otherwise, and it applies to basic economy and nonrefundable fares too. A voucher can replace the refund only if you affirmatively choose it (it must then be valid for at least 5 years), and the airline does not owe the fare difference if the replacement flight you book elsewhere costs more.
A largely historical term - most US carriers no longer have any such rule. Before deregulation, government-filed tariffs included a Rule 240 that obliged some airlines to put you on a competitor's next flight after a delay or cancellation they caused, and the number has survived in travel tips ever since. Today what an airline owes you lives in its contract of carriage, not in a tariff rule number. The modern version of the idea is real, though: several large US carriers commit to rebooking you on another airline at no cost for controllable cancellations - ask for that in plain words, because it is never volunteered.
The trigger for the US refund right, defined by the US DOT automatic refund rule: a delay of 3 or more hours on a domestic flight or 6 or more hours on an international one. A departure or arrival moved to a different airport, a connection added to your itinerary, a downgrade to a lower class of service, or a switch to a less accessible aircraft for a traveler with a disability also count. Cross any of those lines, decline to travel, and you are owed a full cash refund of the unused ticket - see refund vs rebooking above.
Waiting, unconfirmed, for a seat that may open up on a flight you do not hold a reservation on. During disruptions, agents can often add you to standby on an earlier flight while your confirmed seat on a later one stays protected - ask for exactly that, because it is the version with no downside. Whether standby is free or paid, and who qualifies, varies by airline, so check the carrier's contract of carriage. A standby seat is never guaranteed; do not give up a confirmed one for it.
The US DOT rule for when you are stuck on board on the ground with the doors closed. After a set number of hours on the tarmac - the limit differs for domestic and international flights - US airlines must give you a chance to get off the plane, with exceptions for safety, security, and air traffic control. During a long ground wait they must also provide food, water, and working lavatories. The crew is watching the same clock you are, which is why very long sits often end in a gate return.
Giving up your confirmed seat on an oversold flight in exchange for whatever the airline offers - money, a voucher, a rebooking. No law sets the amount for volunteers; it is a negotiation, and offers often improve when volunteers are scarce. Before you accept, get the new flight confirmed (a seat, not standby), ask about a hotel and meals if it means an overnight, and read the voucher's expiration and restrictions. Volunteering generally waives the involuntary denied boarding payment above, so know that number before you raise your hand.
U.S. DOT automatic refund rule, 14 CFR Part 260, effective October 2024 (significant change thresholds of 3 and 6 hours; refund timing of 7 business days and 20 calendar days; 5 year voucher validity) · U.S. DOT denied boarding rules (200 and 400 percent compensation, $1,075 and $2,150 caps) · U.S. DOT Airline Customer Service Dashboard (care commitments for controllable disruptions) · U.S. federal baggage liability rules (about $4,700 domestic cap) · Montreal Convention (about 1,519 SDR international baggage cap) · EU Regulation 261/2004 and its UK equivalent (fixed compensation bands, duty of care).
General guidance, not legal advice. Where a term's specifics vary by airline, the carrier's contract of carriage controls. Facts reviewed August 2026. Found an error? Tell us and we will fix it.