Airline pricing is a complex beast, and while we often focus on the convenience and experience of flying, the systems behind airline ticket pricing are just as fascinating. On any given flight, passengers sitting side by side may have paid dramatically different prices for their tickets.
One way airlines manage revenue and pricing is through fare classes, a system that categorizes every seat on a plane into different pricing tiers with specific rules and benefits. Understanding these fare classes can help you book smarter, maximize airline miles and optimize your chances of securing upgrades.
In this guide, we’ll explain airline fare classes, how they affect ticket pricing and upgrades, and how they impact earning miles in frequent flyer programs and looking for award availability.
What are fare classes?
A fare class (sometimes called a fare bucket or fare code) is a letter assigned to a specific type of airline ticket. Each seat on an aircraft belongs to a fare class that dictates pricing, refundability, upgrade eligibility, baggage allowance and mileage earning potential.
Some fare classes are standard across all airlines, while others vary by carrier. Here are the most common fare codes used across major airlines:
- Y: Full-fare economy-class ticket
- J: Full-fare business-class ticket
- F: Full-fare first-class ticket
Among the large U.S. carriers, Delta Air Lines and United Airlines no longer market any flights with the F fare class, leaving J as the highest fare class available for purchase. American Airlines does use the F fare class, but only for flights offering Flagship First service on its three-cabin aircraft — the Boeing 777-300ER and Airbus A321T.
If you visit frequent flyer forums like FlyerTalk or the TPG Lounge group on Facebook, travelers often use these codes generically when discussing specific service classes (e.g., “I’m flying in Y from New York to London and want to upgrade to J”). However, in this guide, we focus on officially published airline fare classes.
How to read fare classes when you search for flights
Fare classes determine ticket availability and pricing. Below is an example from ExpertFlyer (a paid tool for fare class availability owned by TPG’s parent company, Red Ventures), showing American Airlines flight 38 from Miami International Airport (MIA) to London’s Heathrow Airport (LHR):
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The numbers next to each fare class indicate how many tickets remain available. If a fare class is marked “0,” it means no tickets remain in that bucket. ExpertFlyer displays a maximum of “7,” meaning at least seven seats are available in that fare class.
Here’s how American Airlines categorizes fare classes on its Boeing 777-300ER:
- First class: F, A
- Business class: C, J, R, D, I
- Premium economy: W, P
- Economy class: Y, H, K, M, L, G, V, S, N, Q, O, E
- Basic economy: B
While these codes indicate fares you can purchase with cash (revenue fares), award fares and upgrade inventory also use specific fare classes.
For example:
- “A” can represent discounted first-class or business-to-first-class upgrades.
- “C” is often used for economy-to-business upgrades.
- “W” and “P” are for premium economy upgrades.
Related: Understanding American Airlines’ revenue, award and upgrade fare classes
The most-discounted fares have the strictest rules when it comes to refunds, changes, baggage allowances and earning frequent flyer miles or elite credit. Some airlines don’t award frequent flyer miles at all if you buy a ticket in the most-discounted economy fare class, especially when trying to credit the flight to loyalty programs of partner airlines.
We recommend using a site like CWSI for help deciphering Delta, American, Alaska Airlines, Southwest Airlines and United fare codes.
How fare classes affect ticket pricing
Let’s say you’re booking a flight from Chicago’s O’Hare International Airport (ORD) to Los Angeles International Airport (LAX). When you checked the price yesterday, a round-trip ticket cost $305, but today, the same ticket costs $375.
What happened? Most likely, the cheapest fare class sold out, and only higher-priced fare classes remain.
How fare classes affect earning miles and elite status
When earning frequent flyer miles, your fare class determines how many miles you accrue. While major U.S. airlines like American, Delta and United award miles based on ticket price, some partner airlines still use distance-based accrual models. This may affect you when you go to take the flight, depending on which airline you’re flying with.
For example, here’s how Delta SkyMiles awards miles on an Aeromexico flight:
| Fare class | Miles earned | Medallion Qualification Dollars (MQDs) |
|---|---|---|
| Business — J | 200% | 40% |
| Discounted Business — C, D, I | 200% | 30% |
| Full Economy — W, Y | 125% | 20% |
| Economy — B, M, U | 100% | 15% |
| Discounted Economy — H, K | 100% | 10% |
| Deep Discounted Economy — E, N, R | 50% | 5% |
| Deep Discounted Economy — V | 25% | 5% |
Therefore, if you book a 1,331-mile Aeromexico flight from Mexico City International Airport (MEX) to Hartsfield-Jackson Atlanta International Airport (ATL):
- V fare class: Earns only 333 SkyMiles
- E, N, R fare class: Earns 666 SkyMiles
- Full-fare business class: Earns 1,331 SkyMiles
The website WhereToCredit can be a handy tool to check fare class mileage earning rates for different airlines.
Understanding this information can be critical if you’re looking to earn status. For instance, if you’re chasing Delta Air Lines Medallion status, using the chart above, the lowest economy fare class would get you 1,331 Medallion Qualification Miles but only 5% Medallion Qualification Dollars.
If the base fare of the MEX-to-ATL flight on Aeromexico were $200, you would only earn 10 MQDs. While those numbers would double if you booked into E, N or R, even booking into full-fare business class nets you a maximum of 40% MQDs. Here, Delta is capping the MQD earnings as an incentive for its most loyal travelers to earn status by flying on Delta’s own flights or, at the very least, booking partner flights through Delta.
Related: How to earn miles in the Delta Air Lines SkyMiles program
How fare classes impact upgrades
Airline upgrades aren’t just about availability — your fare class matters. Some fare classes aren’t upgradeable, while others require you to pay an additional cash fee.
For example:
- Basic economy (B, N or O fare classes) are rarely upgradeable.
- Discounted economy (L, K or M) may allow upgrades with restrictions.
- Full-fare economy (Y) is usually fully upgradeable.
Most airlines use designated upgrade fare classes:
- Delta: OU (complimentary Medallion upgrades)
- United: PZ (Premier upgrades)
- Alaska: U (first-class upgrades)*
- American: C (systemwide and mileage upgrades)
*Travelers confirmed into Alaska first class via U class are not eligible for access to the Alaska Lounge.
If you see open first-class seats but can’t upgrade, it’s because the airline has yet to release those seats into the upgrade fare bucket. This sometimes may not happen until 60 or even 30 minutes before departure.
Related: How to upgrade to first class without spending a ton of money
Understanding fare basis codes
A fare basis code is an alphanumeric combination that provides detailed fare rules beyond just a fare class code.
Here’s an example using the United fare basis code KAA2PHEN for a United flight from LaGuardia Airport (LGA) to ORD, found using ITA Matrix.
Each ensuing letter represents a different restriction or rule. If you dig deeper by using the ITA Matrix, you can click through to see the “rules” applied to the code.
In this instance, it breaks down as follows.
- K = Discounted economy fare
- A = Advance purchase required
- A2 = Specific fare rule
- PH = High-season pricing
- EN = Nonrefundable
Fare basis codes can tell an agent whether a fare is refundable, good for one-way or round-trip tickets, departing to or from specific countries, combinable with other fares and good in high or low season. They can also tell an agent how far in advance the fare can be booked and whether there are any routing restrictions or change penalties.
While fare basis codes are complex, understanding your fare class helps determine ticket flexibility and benefits. Fare basis codes can add an unnecessary level of complexity, and for most travelers, it’s not often worth the time to understand much more beyond the fare class and its rules. But at least now you know.
Special fare classes
Some airlines use special fare classes for unique situations:
- CB: Indicates an extra seat for cabin baggage.
- P: Code that Etihad uses for The Residence on A380s
- IN: Infant fare, usually 10% of an adult fare
- CH: Child’s fare, which varies from 0% to 50% savings depending on the airline
- CL: Clergy fare (who knew?)
- DP: Diplomat
- PG: Pilgrim
- YCA: Contracted military/U.S. government fares
Bottom line
Knowing your fare class can save you money, maximize your miles and help you plan better for upgrades. Whether booking flights, earning elite status or redeeming miles, understanding fare classes is key to making smarter travel decisions.
Fare classes impact ticket pricing, refunds, mileage accrual and upgrade eligibility. To maximize perks and benefits, it’s good to get in the habit of always checking your fare class before booking and using tools like ExpertFlyer and WhereToCredit to find the best fares and maximize miles.
If you’re new to TPG, check out our points and miles guide for beginners.