First class codes
* F, A, P, R
On domestic flights, F commonly indicates first class on a two-cabin plane. If a three-cabin aircraft is used, P (for "premium") may be used to distinguish the higher level of service in first class. The R code indicated supersonic transport and was no longer used after the retirement of the Concorde, however with the introduction of the new Airbus A380, Singapore Airlines has re-introduced the R class to distinguish their "Singapore First Suites" as a higher class than regular First Class. The A and Z codes may indicate a first class ticket whose fare is reduced due to restrictions on refunds, advance reservation requirements, or other terms.
The codes in short:
* F = Full-Fare First Class
* P = First Class
* A = First Class Discounted
* R = First Class Suites (currently only Singapore Airlines), and formerly Supersonic (Concorde),
* (a lowercase "n" after any class code indicates Night Service)
Business class codes
* C, J, D, I, Z
On many airlines, C or J indicate full fare business class, whereas discounted and thus restricted and typically non-upgradeable fares are represented by I or Z.
The codes in short:
* C, J, D = Full-fare Business Class,
* I, Z = Business Class Discounted,
* (a lowercase "n" after any class code indicates Night Service)
Economy class codes
* Full fare: Y, B
* Standard fare: M, H, N
* Special or discount fares: G, I, K, L, Q, R, S, T, U, V, W, X
On most airlines, unrestricted economy ticket is booked as a Y fare. Full fare tickets with restrictions on travel dates, refunds, or advance reservations are commonly classed as B, H, or M, although some airlines may use S, W, or others. Heavily discounted fares, commonly T or W, will not permit cabin upgrades, refunds, or reservation changes, may restrict frequent flyer program eligibility, and/or impose other restrictions. Other fare codes such as X are restricted for use by consolidators, group charters, or travel industry professionals.
Most low-cost carriers have greatly simplified the fare classes they use to a handful of cases, unlike the dozens employed by a traditional airline. While some traditional carriers have followed, others continue to prefer price discrimination over commoditization.
The codes in short:
* B = Economy/Coach Discounted
* E = Shuttle Service (No reservation allowed), or Economy/Coach Discounted
* G = Conditional Reservation
* H = Economy/Coach Discounted
* K = Economy/Coach Discounted
* L = Economy/Coach Discounted
* M = Economy/Coach Discounted
* N = Economy/Coach Discounted
* Q = Economy/Coach Discounted
* R = Economy/Coach Heavily discounted
* S = Economy/Coach
* T = Economy/Coach Discounted, or Premium
* U = Shuttle Service (No res. needed/Seat guaranteed)
* V = Economy/Coach Discounted
* W = Economy/Coach Premium
* Y = Economy/Coach
* (a lowercase "n" after any class code indicates Night Service)
