Status: checked against official sources; automated independent review
FREQUENT FLYER GLOSSARY
What are irregular operations?
Irregular operations (usually shortened to irregular ops or IROPS) is the airline term for a disruption — a delay, a cancellation, a diversion or a missed connection — that stops a journey running as ticketed. The phrase matters because once a trip is disrupted, the original schedule stops being the reference point: the airline's published terms take over and decide who is rebooked, onto what, and whether money comes back. Those terms live in a contract of carriage, a document American Airlines publishes alongside its customer service plan and its tarmac delay contingency plan [3], and which United Airlines names, together with the ticket terms and the re-accommodation policies of the carrier operating the flight, as applying to its MileagePlus award tickets [7].
Facts checked: 18 October 2026
Key takeaways
- Irregular operations covers four events — delays, cancellations, diversions and missed connections — and describes the state of a journey rather than the fate of one flight.
- Several sets of rules can apply at once: the operating carrier's contract of carriage, the fare rules attached to the ticket, and any passenger-rights regime that covers the journey. [3] [7]
- Nothing about a disruption is automatically free. There is no universal right to meals, hotels, rebooking or compensation; each depends on the cause, the jurisdiction and the ticket terms.
- Loyalty terms follow the flight. United's MileagePlus rules make award tickets subject to the ticket terms and re-accommodation policies of the carrier on which travel is scheduled, and award no miles or Premier qualifying credits for flight cancellations. [7]
What counts as irregular operations?
The term bundles four kinds of disruption. A delay is a flight running later than scheduled. A cancellation is a flight that will not operate at all. A diversion is a flight that lands somewhere other than its ticketed destination. A missed connection is the knock-on effect, where a late arrival makes the next flight in an itinerary unusable.
Because it describes the journey rather than a single aircraft movement, the term is normally used in the plural. One late aircraft can delay a departure, break a connection two sectors later and leave a passenger stranded overnight — three separate problems produced by one event, each with its own handling.
Everyday use keeps irregular operations for disruption close to the day of travel. A flight retimed weeks in advance is dealt with as a schedule change before departure, and although both can end with a passenger on a different flight, the first is settled in advance and the second at the airport.
Cause is part of the definition rather than an afterthought. A delay, a cancellation and a diversion can each stem from the airline's own operation or from something outside it, and that distinction travels with the disruption into the rules that apply to it.
How does a contract of carriage handle rebooking and refunds?
A contract of carriage is an airline's own set of terms for carrying passengers and bags. It is built into the ticket, which is why it, rather than a general expectation of good service, is where rebooking and refund mechanics sit. American Airlines publishes its conditions of carriage from the customer-service area of its website, alongside its customer service plan and its tarmac delay contingency plan [3].
Loyalty terms point back to the same documents. United Airlines' MileagePlus rules state that MileagePlus award tickets may be subject to the taxes, fees, tariffs, Contract of Carriage, ticket terms, and re-accommodation policies of the carrier on which travel is scheduled [7]. On an award trip flown by a partner carrier, that wording makes the operating carrier's re-accommodation policy the relevant one rather than United's own [7].
It also explains why re-accommodation is a wider word than rebooking. It covers whatever the carrier arranges in place of the original flight — a later departure, a different routing, a seat in a different cabin — and the limits on that arrangement sit in the documents named above rather than in one shared industry standard.
When are meals, hotels or compensation owed?
Care is the part of disruption handling passengers ask about first: food during a long wait, a hotel for an unplanned overnight, transport between the airport and that hotel, and sometimes money on top. There is no universal right to meals, hotels, rebooking or compensation: each depends on the cause of the disruption, the jurisdiction the journey falls under, and the terms of the ticket.
The practical consequence is that three separate questions need separating. What does the airline's own contract of carriage promise? What does the passenger-rights regime covering this journey require? What do the fare rules attached to this particular booking allow? The first is answered in the carrier's published document [3] [7]; the second depends on the jurisdiction; the third travels with the fare, not the flight number.
Exceptions and limits
- Award travel has its own ceiling. Under United's MileagePlus rules, award travel is valid only to destinations served both when the award ticket is issued and at departure, and neither United nor its partners are liable for schedule changes that cancel service to a destination [7].
- Miles can be reached by the same documents. MileagePlus miles are kept in an account until redeemed or forfeited under the programme rules, United's Contract of Carriage or United's fare rules, among other listed grounds [7].
- Cancellations do not earn. Neither mileage nor Premier qualifying credits are awarded for flight cancellations [7].
- Re-accommodation is not only a disruption tool. United's rules say a member who does not comply with published award rules may, at United's discretion, be accommodated on a different flight, seated in a lower class of service, or denied ticketing or boarding, without compensation for that action [7].
- Scope. The carrier-specific terms described here are United's MileagePlus rules and American's published conditions of carriage; other airlines publish their own documents with their own wording [3] [7].
Frequently asked questions
Is a missed connection an irregular operation?
Yes. A missed connection is one of the four standard disruption types, alongside delays, cancellations and diversions, because it breaks the itinerary rather than a single flight. Whether it is treated as part of one journey depends on how the trip was ticketed.
Do you earn miles on a cancelled flight?
Under United's MileagePlus rules, no — neither mileage nor Premier qualifying credits are awarded for flight cancellations [7].
Are award tickets handled differently when flights are disrupted?
They can be. United's rules make MileagePlus award tickets subject to the Contract of Carriage, ticket terms and re-accommodation policies of the carrier operating the flight, and limit award travel to destinations served at both issuance and departure [7].
What is the difference between a schedule change and irregular operations?
A schedule change is a retiming announced before travel; irregular operations describe disruption close to the day of travel, when a flight is delayed, cancelled or diverted and connections break. Both can end with a passenger on a different flight, but they are handled at different stages of the trip.
Sources
Sources checked on 18 October 2026. Programmes not covered here include Delta SkyMiles, the British Airways Club, Air France-KLM Flying Blue and Emirates Skywards, and the passenger-rights rules of individual jurisdictions are outside its scope.
- American Airlines conditions of carriage and customer service documents, checked 18 October 2026
- United Airlines MileagePlus rules, checked 18 October 2026