How do I know what fare letters mean when booking air?


DIS Veteran
Jun 21, 2000
I know that understanding airfares is harder than understanding... well, pretty much anything - LOL! That being said, I discovered over the years that airfare (booking with NWA) climbs on Friday, Sat., Sunday & Monday, and drops in price on Tuesday, with Wednesday being the cheapest fares available. I checked on the flight that I want to purchase and it went up to $242.90 on Sat., we just finalized my DH's vacation work schedule this morning, so I will be buying tickets tomorrow.

Anyway, on the weekend, our flight had an "L" attached to it - $242.90 and this afternoon it just went down to $226.00, with a "T" booking. I thought this refers to the number of seats available, but no seats sold this weekend for this plane, so it seems as if NWA just uses these fare codes to justify price increases on the weekends. Is this the case?

I read through the entire Fare Rules for the trip portion of my ticket (I pretended to purchase it), but it doesn't explain these letters. Any of you very knowledgeable air experts out there know the answer on this one?

Thanks, Tiger
In the old days it was simple. F meant first class. Y meant coach. By now, there's a whole alphabet soup of single- and multiple-letter codes, primarily for various discount fares. These codes represent different fare inventories, and seats can be moved from on inventory to another as the airline seeks to maximize its yield while trying to be competitive with other carriers.

Domestic aircraft themselves typically have two classes of seating -- first and coach -- although smaller aircraft and low-cost carrier aircraft are usually configured with a single class, and some twin-aisle aircraft have three seating classes. But those same aircraft could have dozens of fare classes.

I don't worry much about the letters. I worry about the prices and the restrictions.
Generally, there are three classes that matter to an individual purchasing a domestic ticket: restricted coach (lots of change fees, non-refundable, etc. etc.), unrestricted coach (fully refundable), and first class.

The switch of some seats from L to T is courtesy of some piece of yield management software. Seats can move in and out of a particular inventory based on yield management, seat sales, and overall fare rules. (For example, the lowest fare buckets are often never available on a sunday return from a tourist destination.) From a practical point of view, on NW, the only difference between an L-fare and a T-fare is the price you pay for it. The penalties are probably the same.
I'm a travel agent, so I'll try to explain. It's more info that you might want, but some people get a kick out of this.

It used to be that the government told the airlines what they could charge for tickets. After deregulation, the airlines were allowed to charge whatever the wanted to for a ticket, and the airlines decided to offer serveral differant priced tickets based on the restrictions of that ticket, known as "fare rules". The more restrictive the ticket, the less it cost. Restrictions are advance purchase requirement, non-refundable, penalty for changes, Saturday stayover, minimum stay, date, day of the week, and time of day.

The letter you're asking about is the first letter of a fare basis code. A fare basis code is a series of letters and numbers that are an abreviation of the fare rules. A travel agent or airline agent can look at the code and get a general idea of the fare rules without actually having to look them up. F still stands for first, and Y is now what is known as "full fare coach" or the most you'll pay for the honor of flying coach. The full fare coach is an un-restricted, fully refundable and changeable ticket. Then differant letters are given to the restricted coach fares, and letters can vary from airline to airline. The first letter doesnt usually mean anything, it's basicly used for the airline for capacity control.

Each fair basis code is given a certain number of seats on a given flight. The lowest fare basis may have 20 seats, the next lowest may have 30 seats, and so on. Once the 20 seats in the lowest fare basis are gone, all you can book are the higher fares. But if someone cancels in the lowest fare basis, that "seat" can pop up again in availability. Also, the airline can look at how full the flight is over all, and if it isn't selling at the higher ticket price or if another airline kicks off a fare war, the airline can allot more seats and open up that lower fare basis again.

Some airlines, when you book online, give the first letter of that fare basis code, in your case "L" and "T". They do this, as far as I can tell, because some frequent flyer benifits are increased or decreasd based on what kind of ticket you buy, and the person can then decide to buy a higher priced ticket in another fare basis so they can get their full bennifits. I can't think of any other reason, as it wouldn't mean anything to the average online booker.

So, one of two things happened to you. Either the airline came out with a new fare and gave it it's own new fare basis code, or seats became available in a lower fare basis class either due to a cancelation or seat allotment adjustment.

Again, this was most likely TMI, I hope I didn't bore anyone!

Each airline has its own alphabet soup of fare basis codes.

For Delta, U is the "everyday low price" until the airline decides it has sold enough seats at that price, then L is next lowest. T is the fare war price. Fares can change across the board. It is possible for, say, the L fare to be lower on one day than what the U fare was the week before.

Delta also has one group of coach codes that allow upgrades to first class; L, U, and T codes do not allow such upgrades. Delta does not even have an easy to understand distinction for each of its fare codes, the caption (excursion fare, deep discount fare, promotional discount fare) in English is the same for some of the codes in a recently published synopsis (I forget the web site).

In the old days (at least the 1960's) there were just three codes, F for first class, Y for "coach", and K for "economy" the latter on some airlines not including a meal. Most airlines still use the letter K for one of the discounted coach fare codes.

Disney hints:
Thanks all! Very fascinating info for a teacher like myself who craves knowledge and facts!

I'm off to book our airfare now, Tiger
in the travel industry it has been documented that most people travel on friday through monday. therefore the airlines discount their tues wed and thurs tix so that they can attract more business on those days and not have to run half empty planes. better to sell the seats at a loss than not at all.

Adrienne :wizard:


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