Fare Rule CATS: A Practical Guide
Demystifying ATPCO’s Category System—what each CAT means, where it came from, and how airlines apply them in the real world.
Purpose & History
The Category Control Coding (CATS) system was introduced by ATPCO in the late 1980s to replace free-text fare rules with structured data. Each numbered Category (“CAT”) captures a specific commercial restriction—making automated pricing and accurate fare distribution possible across GDSs, NDC APIs, and airline e-commerce.
- Consistency & Automation — rules price the same worldwide.
- Efficiency — airlines load once, distributors consume everywhere.
- Granularity — tweak one restriction without rewriting the whole rule.
CAT-by-CAT Reference & Examples
CAT 01 – Eligibility
Defines who may buy the fare—age, affiliation, residency (student, senior, military, corporate ID, etc.).
✈️ Example: Emirates student fares require passengers ≤ 32 years plus university ID at check-in.
CAT 02 – Day / Time
Limits departures to specific days of week or times of day; often used to steer leisure traffic to off-peak periods.
🌙 Example: Lufthansa intra-EU business fare requires departures after 19:00 Friday.
CAT 03 – Seasonality
Specifies permitted travel seasons or blackout windows.
🏖️ Example: United promo economy valid only 15 Jun – 31 Aug.
CAT 04 – Flight Application
Restricts flight numbers, operating carriers, codeshares, aircraft type, or routing strings.
✈️ Example: ANA fare requires NH-operated trans-Pacific segments; UA codeshare not allowed.
CAT 05 – Advance Reservation / Ticketing
Lead-time rules for booking or ticketing (e.g., 14-day advance, ticket within 24 h).
⏰ Example: Delta Basic Economy must be ticketed ≥ 21 days prior.
CAT 06 – Minimum Stay & CAT 07 – Maximum Stay
Earliest and latest return limits (e.g., Sat-night stay, max 3 months).
🛌 Example: BA leisure fare: Sat-night min stay, complete travel ≤ 30 days.
CAT 08 – Stopovers
Rules for stops > 24 h (intl) or > 4 h (dom). May allow X free stops or charge fees.
🌍 Example: Singapore Airlines RTW fare allows one free SIN stopover.
CAT 09 – Transfers
Limits intermediate connections under 24 h; can force or prohibit certain hubs.
🔄 Example: JetBlue domestic fare permits max two connections each way.
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CAT 10 – Combinability
Governs open-jaw, end-on-end, circle-trip combinations and HIP checks.
🔗 Example: KLM long-haul fare may combine end-on-end with intra-EU sectors.
CAT 11 – Blackout Dates
Lists dates travel is not permitted (peak holidays, events).
🚫 Example: Qantas blocks SYD-LAX promo fares 15–24 Dec & 2–10 Jan.
CAT 12 – Surcharges
Adds YQ/YR or seasonal surcharges to the base fare.
💰 Example: Emirates fuel surcharge added ex-SYD.
CAT 13 – Accompanied Travel
Companion or 2-for-1 rules; minimum party size, ID verification.
👥 Example: Icelandair “Buddy Fare” requires ≥ 2 passengers booked together.
CAT 14 – Travel Restrictions
Carrier or government bans—specific airports, dates, or embargoes.
🚫 Example: Korean Air promo blocks ICN transfers during Chuseok.
CAT 15 – Sales Restrictions
Point-of-sale, ticketing channel, currency or form-of-payment limits.
🛒 Example: Air France fare must be ticketed in FRA, paid in EUR.
CAT 16 – Penalties (Legacy)
Text-based change/cancel/no-show penalties—still used if CAT 31/33 aren’t populated.
🔧 Example: AA non-ref fare: US$200 change fee.
CAT 17 – HIP / Surcharges Check
Ensures through fare is not less than sum of higher intermediate point fares; may add surcharges.
🧮 Example: NYC-LON-PAR ticket re-prices if NYC-PAR fare is higher than NYC-LON + LON-PAR.
CAT 18 – Endorsements / Restrictions
Text auto-printed in the ticket endorsement box (e.g., NONEND, NONREF, tour codes).
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🖋️ Example: Corporate ticket auto-shows “CORP XYZ ONLY – NONEND.”
CAT 19 – Discounts
Percentage/fixed discounts for child, infant, military, etc.
👶 Example: LH child (2–11) pays 75 % of adult fare.
CAT 20 – Tour Conductor
Free or reduced seats for group escorts (e.g., 1 free per 15 pax).
🚌 Example: Emirates grants 100 % discount for tour leader on ≥ 16 pax groups.
CAT 21 – Agent Discounts
Industry/ID 75/ID 90 fares for airline or travel-agency staff.
🎟️ Example: Delta ID 90 fare for verified airline employees.
CAT 22 – All Other Discounts
Catches niche discounts not covered by 19 / 20 / 21.
🏷️ Example: Humanitarian / missionary discount code.
CAT 23 – Miscellaneous Fare Tags
Flags such as “one-way fare may be doubled” or currency overrides.
🏷️ Example: Leisure fare tagged “OW/RT not combinable.”
CAT 25 – Fare By Rule
Net or private fares built algorithmically off a public base (e.g., 80 % of YY fare).
🔐 Example: Consolidator fare at 70 % of published fare using CAT 25 tour code.
CAT 31 – Voluntary Changes (Automated)
Structured change rules replacing legacy CAT 16 text; enables instant repricing.
🔄 Example: Jetstar allows free date changes online ≥ 14 days before travel.
CAT 33 – Voluntary Refunds (Automated)
Automated refund fees or percentages.
💳 Example: Southwest: full refund to original form of payment pre-departure.
CAT 35 – Negotiated / Private Fares
Corporate, tour, or private fares with ticket designators; bypasses public fare checks.
🎟️ Example: Contract fare ‘CORPXYZ’ only visible to the booking TMC.
Reading CATS Like a Pro
- CAT 31 & 33 override CAT 16 when populated—check automated sections first.
- Blank CAT = Default applies (general rule or industry standard).
- Sequence matters: pricing engines evaluate CATs sequentially; one violation invalidates the fare.