A FlightStats.com Primer: How to Access Airline Fare Class Availability for Free

The FlightStats.com website is a really useful tool — not just for tracking flights, to see whether they’re on time, and looking up historical flight reliability data (which is how most savvy fliers use it) but also to look up availability of seats on specific flights, including availability by specific “fare classes” which are the letter codes of the different buckets of inventory that airlines use.

That may not seem like something that matters to you, but it’s incredibly useful! Here are some examples of how you can use the information.

  • For awards:
    • Say that you have Delta miles and want to know whether Saudi Arabian has business class award space from New York JFK to Riyadh.

    • Or you have Chase Sapphire Preferred points and want to know whether it makes sense to transfer those to Korean in order to redeem for a first class seat on the A380 from JFK to Seoul.

  • During Irregular Operations: You want to search for flights that have availability, whether it’s wide open or just a single seat for sale, in order to tell your airline how to get you home. Maybe you’re trying to go from San Francisco to Washingtn Dulles and United says everything is sold out. But you find 1 seat flying to Kansas City of all places and then on to DC. Or you’re flying up from Atlanta, your plane goes mechanical, and you see seats on a Delta flight. Knowledge is power in knowing what to ask for that the agents might not proactively offer to you.

  • To find the lowest fares: You know that there’s a $500-ish fare to Istanbul. In fact, it’s $200-ish plus taxes and fuel surcharges, and you’re looking to find it on Delta. Delta has it published as a “T” fare. So you want to go searching for flights with availability (a number greater than 0) in the “T” bucket. Just search flights on FlightStats for flights that have T availability, and those flights ought to price as-desired, provided you’re also meeting advance purchase, minimum stay, and any other restrictions like specific days of the week you can travel on the fare.

  • To make same-day confirmed changes: United will allow you to change your flights ($75 for general members and Premier Silvers, free for higher level elites) beginning 24 hours prior to scheduled travel, to any flight within 24 hours of your request, provided that the same booking class as your existing ticket is available on the flight you want. Rather than hoping for a helpful agent, you can research for yourself what flights you can same-day confirmed onto.

FlightStats allows you to search availability up to 299 days out. While it pulls data from Sabre, it does not offer access to American Airlines inventory.

Here’s how to use it.

  1. Create a free account, since you need to be logged in to access the availability feature.

  2. Under the “Flights” menu, choose Flight Availability

  3. Click the ‘advanced’ button so you can specify airline (and for that matter, search connections via a specific city)

Here’s a search for space on Alaska Airlines between Seattle and Los Angeles on November 7, a day I picked at random.

airline fare class availability

The results show a list of flights. Remember, I restricted the search to only find flights on Alaska. You’ll see flight number, airline, departure and arrival times, and also a rating of the flight’s reliability.

airline fare class availability

I clicked the arrow on the left side of the results for the 10am flight, and got full details of availability by each fare ‘bucket’.

There are “at least” 7 first class seats available. Alaska won’t display more than 7 seats in a given bucket, so when you see a seven that means “7 or more.”

What do the different classes mean? 7 “F” (full fare first class) seats are available, at least. There are also 7 “U” seats which means that confirmed upgrades are available. And there are 2 “A” seats meaning two first class award seats — bookable with Alaska miles or miles from any of Alaska’s partners.

All of the coach revenue booking classes, from Y on down, have plenty of availability. The only booking class that’s not showing 7 is “W” — that shows 4, and is the bucket for coach awards. There are 4 economy award seats open on this flight.

How do you know, though, what the different classes mean, especially for award and upgrade classes? This system doesn’t show those ‘special classes’ for all carriers, but it’s available for more than a handful.

With thanks to the KVS Tool FAQ (I’ll be reviewing KVS Tool in a future post), here are some notes on award and upgrade booking codes that are searchable using the FlightStats website.

    Aerolinas Argentinas: “U” (business class award), “X” (economy award), “I” (business class upgrade)
    Aer Lingus: “U” (business class award), “T” (economy award)
    Aeromexico: “R” (business class upgrade)
    Aeroplan: “R” (business class upgrade)
    Aircalin: “O” (business class award), “X” (economy award)
    Air Europa: “Z” (business class award), “A” (economy award)
    Air France: “O” (business class award)
    Air Tahiti Nui: “A” (first class award), “I” (business class award), “W” (economy award), “Z” (business class upgrade)
    Alaska Airlines: “A” (first class award), “U” (first class upgrade), “W” (economy award)
    Avianca: “A” (business class award), “Z” (economy award)
    Bangkok Airlines: “Y” (economy award)
    Brussels Airlines: “I” (business class award or upgrade), “X” (economy award)
    CCM Airlines: “X” (economy award)
    China Eastern: “A” (first class award), “D” (business class award), “I” (economy award)
    China Southern: “P” (first class award), “I” (business class award), “O” (economy award)
    Czech Airlines: “Z” (business class award), “E” (economy award), “I” (business class upgrade)
    El Al: “P” (first class award), “X” (business class award), “E” (economy award), “A” (first class upgrade), “R” (business class upgrade)
    Etihad: “R” (first class upgrade), “X” (business class upgrade)
    Gol: “I” (business class award), “X” (economy award)
    Gulf Air: “P” (business class award), “T” (economy award)
    Hainan Airlines: “A” (business class award), “S” (economy award)
    Hawaiian Airlines: “U” (economy award), “P” (first class upgrade)
    Icelandair: “Z” (business class award)
    Korean Airlines: “A” (first class award/upgrade), “Z” (business upgrade)
    Martinair: “W” (economy award)
    Saudi Arabian: “A” (first class award), “D” (business award), “L” (economy award)
    Shanghai Airlines: “O” (first class award), “I” (business class award), “X” (economy award)
    Tarom: “Z” (business class award), “X” (economy award)
    Transaero Airlines: “E” (economy award)
    Turkish: “J” (business class upgrade using Miles&Smiles miles)
    Virgin Australia: “H” (business class award)
    VLM Airlines: “O” (business class award), “P” (economy award)

    Note that “upgrade” booking classes generally apply to using the miles associated with the airline’s own frequent flyer program only, using miles on partner airlines will generally imply a different booking class (e.g. Star Alliance upgrades usually pull from award booking classes).

Let’s have a look now at Korean. Searching New York to Seoul I come up with the following on the Airbus A380.

There are 4 first class award seats open. Wow, that’s generous. I sure wish Delta allowed their miles to be used for awards in international first class! Lucky I have Chase Ultimate Rewards points…

There’s also 4 business class upgrades, so I can upgrade if I’m buying an eligible fare and using Korean Airlines miles.

Unfortunately this system doesn’t show Korean’s business class award space, which would be ideal for the Delta Skymiles crowd — you cannot search for Korean Airlines business class awards online unless you have an account with Korean that has enough miles in it to claim the award. And Korean inventory may differ slightly from what a Delta agent will offer. So you still have to call Delta and hunt and peck (and of course Delta applies much more draconian blackout dates to awards on Korean than Korean applies to its own members).

All in all, a useful tool for searching for flights, finding lowest fares, and scouring for awards and upgrades. Definitely bookmark-worthy.

About Gary Leff

Gary Leff is one of the foremost experts in the field of miles, points, and frequent business travel - a topic he has covered since 2002. Co-founder of frequent flyer community InsideFlyer.com, emcee of the Freddie Awards, and named one of the "World's Top Travel Experts" by Conde' Nast Traveler (2010-Present) Gary has been a guest on most major news media, profiled in several top print publications, and published broadly on the topic of consumer loyalty. More About Gary »

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  1. […] That’s about all from my week in China. I did explore a Delta+Gol award for a potential summer Brazil trip with friends. I got the Delta segments to price low economy on the outbound, mid economy on the indound, put them on hold. Either the system was wrong or the agent or both, and I was calling during the middle of the US night on a weekend. Adding the Gol segement to the existing hold or starting a new reservation was adding 20,000 miles to the price, treating the ticket as two separate trips a US-Brazil and a Brazil domestic. The trip fell through before I steeled myself for a Monday of calling. Good to see decent Gol availability a few months out, you can check on Flight Stats. […]


  1. Great post, Gary. I feel this could be a potential replacement for “light” users of EF and KVS.

  2. Great post!

    Quick comment though: EL-AL first class award is “P” not “F”…

  3. Yep – definitely a contender for blog post of the week! I’d been looking for the award fare “bucket list”- thanks.

  4. Gary, how do you know that the Alaska Airlines “W” was for economy award ticket? I check the code legends under Alaska Airlines and it does not specify which is the award ticket.

    Also, on CX, can one actually book an premium economy award ticket?

  5. @Gary I just went to FlightStats website yesterday to try it out and did not find the availability menus. Now I know that I need an account and need to log in there. My EF subscription is ending today, talk about timing of your post. May be I will not renew EF and try out FS for a while.

  6. @lkonos – well, I have a post on what I use Expertflyer for coming up, stay tuned as they say 🙂

  7. @Dave OP – Alaska does offer Premium Economy redemption. And as for W, well, “because I know” 😉

  8. On my android, until 2 months ago i could access the http://www.flightstats.com full site to log-in and search availability. Since then, they have implemented something where even if you click “flight availability” it kicks you back to the mobile site, where the flight availability doesn’t show.

  9. I guess what I really need is a definitive list of what those pesky fare class letters mean for all airlines, and especially for U.S. Airlines. Anyone who publishes such a list will earn my eternal gratitude and a reference on my website.

  10. What a post? Thanks a lot Gary, I was trying to learn different airfare class and how to search for them and this post is just right on target
    Thanks a bunch

  11. Thanks! I usually use ExpertFlyer but I know not everyone pays (or wants to) for this info 😛 FYI you’ve got Aeroplan listed instead of Air Canada, and you’re missing X for Economy and I for Business awards. Most Star Alliance carriers are trying to harmonize on O / I / X after all.

  12. FS is probably going to hide this functionality a bit further since the KVS tool systematically scrapes FS for a significant portion of their results 🙁

  13. I am curious if an airlines is showing basically a wide open economy seating but not selling their T fares only U, does that mean they are holding onto the T fares for a later time or that they might never decide to sell T fares for that specific flight?

  14. @oliver2002 — FlightStats is PROUD of this functionality, I had an exchange with them yesterday, they were asking permission to highlight my post on the front page of their site.

  15. @oliver2002 – they could definitely add a minimum segment requirement on their own flights to earn the status, or introduced two-tiered earning (# of miles on their aircraft vs on partners). The question then is what they would do with existing Golds. Eventually, surely, they’ll have to expire status as the ranks will swell over time

  16. Hey Gary — Great info, thanks! However, I noticed that you did not like American Airlines…can one lookup those fAAre clAAsses using this tool?

  17. Gary, I am not sure if use N code for UA correctly as economy award, but, for example UA956 on Sept. 7 shows N=0, but search for the saver award on UA website shows more than 1 seat available. What I am doing wrong? Thanks!

  18. This is a great post! Does anyone have the codes for United? I don’t see them listed anywhere and they are on FS. Thanks!

  19. Gary, Is it correct to say that Air France no longer shows Business Class Award fare class O anymore (e.g., thru ExpertFlyer)? I checked ExpertFlyer for JFK-CDG flights on 12/24 and don’t see any O fare, but I found Business Class award space at airfrance.com.

  20. The transatlantic must now be under a code different from O, as they are still available on airfrance.com.

  21. @worldtraveler2018 – i just think that publication of O inventory is being suppressed through those channels. It still appears intra-Europe and Europe-Asia. And Skyteam has been converging on O as the bucket for business class awards, across carriers.

  22. I frequently refer to this, what I can’t figure out is why flight stats sometimes shows flights and sometimes not, depending on searches. It can be very odd, for instance last week I could not get Saudi Arabian nonstops to NY to show unless I searched for Dubai to NY on them and then the nonstops popped up as part of connecting itineraries. I have had similar problems with Gol on Brazil flights. I usually can eventually find the flights but it is trial and error with routings.

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