Key takeaways
- Airlines run on rules: fare rules, refund and compensation entitlements, rebooking priorities, baggage policies, loyalty benefits, crew duty limits and maintenance intervals.
- A business rules engine keeps these rules in one place, applies them the same way in every channel, and records which rule produced which decision.
- Passenger rights rules are tightening. In the US, DOT requires automatic cash refunds for significant schedule changes and cancellations. In the EU, lawmakers agreed in June 2026 on an overhaul of air passenger rights that adds claim deadlines and rerouting obligations.
- Optimization tools and machine learning find the best options; rules decide what each passenger is entitled to and what the airline's policy allows.
- In safety-critical areas such as crew duty and maintenance, rules support qualified staff and approved programs; they do not replace them.
What does a business rules engine do in airline operations?
A business rules engine is software that applies explicit if-then logic to data and returns a decision: eligible or not, which option, which amount, which next step. Airlines already have this logic everywhere - in fare filings, contracts of carriage, customer service scripts, loyalty terms and operations manuals. The rules engine moves it out of scattered code and documents into one place that the teams who own it can read, test and change.
The value shows most during irregular operations. When hundreds of flights are disrupted at once, every passenger's entitlements must be worked out quickly and correctly, and every agent, app and kiosk must give the same answer. For the fundamentals of rules engines, see What Is a Rules Engine?.
Which airline decisions are rule-based?
Most of these decisions change often. Fare rules and promotions change weekly, partner agreements change by contract, and passenger rights rules change by regulation.
How are US and EU passenger rights rules changing?
United States. Under DOT's final rule on automatic refunds, announced on April 24, 2024, airlines must refund passengers when a flight is cancelled or significantly changed and the passenger does not accept the alternative. A significant change includes a departure or arrival time moved by more than 3 hours domestically or 6 hours internationally. Refunds must be automatic, in cash or the original form of payment, and issued within seven business days for credit card purchases and 20 calendar days for other payment methods. The rule also covers delayed checked bags (not delivered within 12 hours domestically, 15–30 hours internationally) and ancillary services paid for but not provided (US DOT, April 2024).
European Union. On June 15, 2026, the Council and the European Parliament reached an agreement to reform EU air passenger rights. Compensation remains available when a flight arrives more than three hours late, at €250, €400 or €600 depending on distance. Airlines would have to send passengers information on their rights and how to claim within 96 hours of arrival, acknowledge claims immediately and pay or justify a refusal within 30 days. After a cancellation or denied boarding, passengers choosing rerouting at the earliest opportunity must get an alternative within three hours, or may arrange their own and claim up to 400% of the original ticket price. The agreement still needs formal adoption by both institutions (Council of the EU, June 15, 2026).
For an airline flying under both regimes, one disrupted itinerary can trigger two different sets of entitlements. That is a rules problem, and it is expensive to solve by hand.
What does a disruption rule look like?
Here is a simplified decision table for passenger entitlements after a disruption. It is illustrative only and not legal advice:
In a rules engine, each row has an owner (legal, customer service), a source (regulation, contract of carriage) and a version. When the EU reform is formally adopted, the team adds new rule versions with the new claim deadlines and rerouting rules, tests them on past disruptions, and schedules them for the date the rules apply.
How do rules work with optimization tools and machine learning?
Airlines use optimization software to rebuild schedules, crew pairings and passenger itineraries after disruptions, and machine learning to predict delays, component failures and passenger preferences. Rules play a different role: they define what is allowed and what each passenger is owed.
A common pattern during irregular operations: the optimizer proposes, the rules decide, and every decision is logged. The optimizer returns candidate itineraries; rules filter them by fare class, partner agreements and the passenger's entitlements, rank them by status and connection risk, and attach the refund, compensation and care each passenger should receive. Agents, the app and airport kiosks all show the same result.
Maintenance works the same way, within stricter limits. Predictive models can flag a component that is likely to fail. What happens next is governed by the airline's approved maintenance program and the aviation authority's requirements. Rules can make sure a flagged item creates the right task, with the right deadline, in the maintenance system; the decision to release an aircraft stays with certified staff. Crew duty checks follow the same principle: rules check a proposed assignment against duty and rest limits and labor agreements, and crew schedulers make the call.
What should airlines look for in a rules engine?
- Business ownership. Can revenue management, customer service and legal read and change the rules they own?
- Jurisdiction-aware rules. Can one decision apply US, EU and other regimes to the same itinerary?
- Testing on past events. Can you replay last month's disruptions through a new rule version and compare results?
- Scheduled versions. Can a new rule set be prepared in advance for the date a regulation or fare change applies?
- Audit trail. For any passenger, can you show which rules applied and why a refund or compensation was paid or refused?
- Performance. Can the engine answer in real time when thousands of passengers are affected at once?
- Integration. REST API or SDK access from reservation, departure control, customer service and mobile channels.
Where does Higson fit?
Higson is a business rules engine built by Decerto, used mainly by insurers and financial services companies. It has no airline-specific modules, and we do not claim airline customers. Its general capabilities fit the rule-heavy decisions described above:
- Decision tables that business teams maintain and test, with imports from Excel through CSV.
- Versioning, rollback and a full audit trail, with role-based permissions by business domain in Higson 4.3 LTS.
- Real-time performance: rule execution takes 0.23 ms per decision, with throughput of 9,000 requests/second.
- Machine learning inside rules through an ONNX runtime, so a model score and the policy around it are evaluated together.
- Integration and deployment: REST API and Java SDK; cloud, on-premise Kubernetes or hybrid.
With rules managed this way, customer service and legal teams own entitlement logic, which removes backlog from the IT queue and gives IT more time for architecture and integrations.
The closest match to Higson's core market is travel insurance. Flight delay, cancellation and baggage coverage are triggered by the same events as airline refunds and compensation, and insurers use rules to decide eligibility and payouts.
Related articles
What Is a Rules Engine?
Why a Recommendation Engine for E-Commerce Boosts Sales
Rules Engines in Healthcare
Sources
- US DOT, „Biden-Harris Administration Announces Final Rule Requiring Automatic Refunds of Airline Tickets and Ancillary Service Fees" - https://www.transportation.gov/briefing-room/biden-harris-administration-announces-final-rule-requiring-automatic-refunds-airline
- Council of the EU, „Council and Parliament reach landmark agreement on stronger EU air passenger rights" - https://www.consilium.europa.eu/en/press/press-releases/2026/06/15/council-and-parliament-reach-landmark-agreement-on-stronger-eu-air-passenger-rights/
- Flight-Delayed.com, EU261 - https://www.flight-delayed.com/en/news/2026/06/04/eu261-reform-deadlock-air-passenger-rights
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