A Guide to the Most Important Airline Fare Filing Terminology and Acronyms

Every airline ticket starts with a code. Behind each flight price lies a web of acronyms and terminology. These terms don’t just describe fares—they control pricing, availability, and compliance. For beginners, the jargon can feel like a foreign language.

This guide will decode the most important fare filing terminology so you can work smarter, faster, and with confidence.

1. Fare Basis Code (FBC)

The Fare Basis Code is the foundation of every ticket price. It’s a string of letters and numbers that defines the fare’s rules, restrictions, and class. Without it, there’s no way to differentiate between a fully refundable business class ticket and a non-refundable economy fare.

• Why it works: Fare Basis Codes standardize ticket rules across systems, ensuring consistency.

• Structure defines purpose: For example, “Y” might indicate economy class, while “F” stands for first class.

• Rules in the details: Codes include conditions like advance purchase requirements or minimum stays.

Understanding FBCs lays the groundwork for mastering fare filing.

2. RBD (Reservation Booking Designator)

The RBD is a code tied to the fare class and controls seat inventory. It determines which seats can be sold at specific fare levels. Airlines use RBDs to balance supply and demand while optimizing revenue.

• Why it works: RBDs group seats into categories, ensuring pricing aligns with availability.

• Dynamic adjustments: Airlines open or close RBDs based on booking trends.

• Ties to flexibility: Higher RBDs often allow more flexible terms, like free changes or refunds.

Think of RBDs as the key to managing seat availability efficiently.

3. GDS (Global Distribution System)

GDS platforms like Amadeus, Sabre, and Travelport are the central hubs for fare filing. They connect airlines with travel agents, OTAs (Online Travel Agencies), and other sales channels. Without GDS, fare distribution on a global scale wouldn’t be possible.

• Why it works: GDS simplifies fare distribution, reducing errors and manual work.

• Centralized updates: Airlines can update fares for multiple channels instantly.

• Global reach: GDS ensures fares are accessible to agents worldwide.

  
  

GDS is the backbone of fare filing, making it indispensable to the process.

4. PNR (Passenger Name Record)

A PNR is a unique identifier for every booking. It contains passenger details, itinerary, and fare information. Fare filing ensures that the PNR reflects accurate pricing and ticketing rules.

• Why it works: PNR links all booking details in one place, ensuring seamless record-keeping.

• Central to changes: Fare adjustments or refunds are processed through the PNR.

• Compliance tracking: PNRs help airlines comply with passenger data regulations.

Accurate fare filing ensures the PNR reflects the correct fare conditions.

5. ATPCO (Airline Tariff Publishing Company) and Airline Fare Filing Terminology

ATPCO is the central clearinghouse for fare filing. It processes and distributes airline fares and rules to GDS and other systems. Most airlines rely on ATPCO to ensure their fares are filed and updated accurately.

• Why it works: ATPCO standardizes fare filing, eliminating inconsistencies.

• Streamlined updates: Airlines can modify fares in one place and distribute them globally.

• Industry-wide adoption: Nearly all airlines and GDS platforms use ATPCO.

Without ATPCO, fare filing would be a fragmented and error-prone process.

6. IATA (International Air Transport Association)

IATA sets global standards for airline pricing, fare filing, and ticketing. Its codes and guidelines ensure consistency across the aviation industry. Airlines must adhere to IATA regulations when filing fares.

• Why it works: IATA simplifies international operations by creating universal fare standards.

• Codes for everything: IATA codes govern currencies, airports, and even fare types.

• Global compliance: Fare filing systems must align with IATA rules to avoid penalties.

IATA serves as the rulebook for fare filing across borders.

7. OW (One-Way Fare)

A One-Way Fare allows passengers to travel in a single direction. These fares are typically less restrictive but more expensive than round-trip fares. Fare filing systems must distinguish between OW and round-trip pricing.

• Why it works: OW fares offer flexibility for passengers with unique travel needs.

• Dynamic pricing: Airlines adjust OW fares based on route demand.

• Transparency matters: Fare filing ensures OW rules are clear to passengers.

  
  

OW fares are a key component of any robust fare filing strategy.

8. RT (Round-Trip Fare)

Round-Trip Fares are designed for passengers traveling to and from the same destination. They’re often cheaper than booking two separate one-way fares. Fare filing ensures RT pricing reflects the total cost of both legs.

• Why it works: RT fares encourage passengers to book return flights with the same airline.

• Rules and restrictions: RT fares may require specific departure and return dates.

• Bundled savings: Fare filing systems calculate discounts for RT bookings.

RT fares are a cornerstone of competitive pricing strategies.

9. Surcharges (YR / YQ)

YR and YQ are codes for carrier-imposed surcharges, like fuel fees. These fees are separate from base fares but are included in the total price. Fare filing systems must account for surcharges accurately.

• Why it works: Surcharges cover fluctuating costs, like fuel or security expenses.

• Dynamic adjustments: Airlines update surcharges based on market conditions.

• Transparency is key: Fare filing ensures fees are clearly labeled for passengers.

Surcharges are vital for offsetting variable costs without altering base fares.

10. AP (Advance Purchase)

Advance Purchase rules specify how far in advance a ticket must be bought. These rules often apply to discounted fares. Fare filing systems enforce AP requirements to prevent misuse.

• Why it works: AP rules reward passengers who book early, helping airlines manage demand.

• Discount thresholds: The earlier the booking, the lower the fare.

• Helps with forecasting: AP data aids in revenue and capacity planning.

Advance Purchase rules balance customer incentives with operational efficiency.

11. Min / Max Stay

Minimum and Maximum Stay rules control how long passengers can remain at their destination. These rules are often tied to discounted fares. Fare filing ensures these restrictions are applied consistently.

• Why it works: Stay rules encourage return bookings within specific timeframes.

• Weekend triggers: Many fares require a minimum Saturday night stay.

• Flexibility adds cost: Higher fares offer greater freedom with stay lengths.

Min / Max Stay rules are integral to managing fare categories and pricing tiers.

12. Stopover vs. Layover

A stopover is a planned stop lasting over 24 hours, while a layover is under 24 hours. Fare filing systems must distinguish between the two for pricing and ticketing purposes.

• Why it works: Stopovers often incur fees or require additional fare rules.

• Incentivizing travelers: Airlines may offer free stopovers to promote certain cities.

• Layovers simplify connections: Short stops are typically included in the base fare.

Clear stopover and layover rules enhance transparency and passenger satisfaction.

13. NUC (Neutral Unit of Construction)

NUC is a standard currency used in international fare calculations. It simplifies pricing across multiple currencies and exchange rates. Fare filing systems rely on NUC to ensure global consistency.

• Why it works: NUC eliminates confusion caused by fluctuating exchange rates.

• Universal adoption: All IATA-compliant airlines use NUC for fare calculations.

• Accurate conversions: Fare filing systems convert NUC into local currencies seamlessly.

NUC is the invisible thread binding global fare structures together.

14. Non-Endorsable Tickets

Some fares are non-endorsable, meaning passengers can’t transfer them to other airlines. Fare filing systems enforce these restrictions to protect revenue.

• Why it works: Non-endorsable rules prevent fare misuse and unauthorized ticket transfers.

• Protecting alliances: Some exceptions apply for codeshare or interline agreements.

• Customer clarity: Fare filing ensures passengers know their ticket limitations.

Non-endorsable tickets safeguard airlines’ pricing integrity.

15. CAT 25 Fares

Category 25 fares are private or negotiated fares not publicly displayed. They’re often used for corporate contracts or travel agencies. Fare filing ensures these fares remain confidential and properly distributed.

• Why it works: CAT 25 fares offer flexibility for specialized contracts.

• Targeted distribution: These fares are only accessible to authorized parties.

• Revenue opportunities: Airlines use CAT 25 to attract high-value clients.

CAT 25 fares highlight how fare filing can be tailored to client-specific needs.

Fare filing acronyms and terminology aren’t just technical details—they’re the building blocks of airline pricing. Mastering these terms empowers you to manage fares with precision and confidence.

When you understand the language of fare filing, you unlock smarter pricing strategies and stronger results.

Ready to learn more? Speak with the Anjuna team to explore solutions tailored to your fare filing challenges.