How Can I Tell When Airlines Have Available Upgrade Space?

Apr 23, 2019

This post contains references to products from one or more of our advertisers. We may receive compensation when you click on links to those products. Terms apply to the offers listed on this page. For an explanation of our Advertising Policy, visit this page.

“Reader Questions” are answered twice a week by TPG Senior Points & Miles Contributor Ethan Steinberg.

If you absolutely need a lie-flat bed or a large hotel suite in order to enjoy your trip, you’re always best booking it outright instead of waiting and hoping for an upgrade to clear. Still, if you hold elite status or are willing to spend some extra cash or points, upgrades can be a great way to travel in a little more comfort than you actually need. TPG reader Jake wants to know how he can make sure his upgrades will clear before the flight …

I’m flying to Maui on American Airlines with my family and trying to request a cash+points upgrade. They say the upgrade isn’t available and we’d be waitlisted. Is there any way around this to confirm our upgrade in advance?


Unfortunately, just because there are open seats in business or first class doesn’t mean you’ll be allowed to upgrade. Even if you’re willing to redeem an upgrade certificate, spend cash or use your miles, you typically can only clear an upgrade in advance if the airline has set aside seats in its “upgrade” fare class. While most travelers can get by without paying attention to this nuance of a trip, it’s important to understand fare classes if you’re trying to score a seat up-front. Let’s take a look at the different upgrade fare codes for the three major US legacy carriers.

American Airlines

Since Jake asked about American Airlines, we’ll start here. Even though American Airlines has 26 different fare classes, one for each letter of the alphabet, there are only two you need to pay attention to for upgrades:

  • “C” inventory is for a one-cabin upgrade to business class (or two-cabin domestic first class)
  • “A” inventory is for an upgrade to first class on three-cabin aircraft, which only applies to American’s Boeing 777-300ERs and specially configured Airbus A321Ts (for transcontinental routes).

ExpertFlyer is a great tool to help in your quest for these upgrades. As soon as you select American Airlines, the following list of fare classes will pop up for you to search.

These fare classes apply for just about any type of upgrade you can think of, including Systemwide Upgrades (SWUs), mileage upgrades or upgrades using Business Extra points.

While American is quite stingy with its business class (“C”) upgrade space, I find that first class (“A”) is often wide open, especially on American’s premium transcontinental routes.

ExpertFlyer is also great for its alerts feature, which could help Jake’s goal of upgrading his flight to Maui. If his flight doesn’t have upgrade space available, he can set an alert for his desired number of seats and receive an email if they open up. Even if he’s on the waitlist, there’s no guarantee that American will automatically process his upgrade. Once he gets word of enough available seats, he should call to make sure he and his family can ride up front.

United Airlines

United has a slightly more complicated set of upgrade fare codes. Not only does it differentiate based on the class of service to which you’re upgrading; it also uses different fare classes for different elite status tiers. Further complicating things is that United overhauled its fare classes just a few months ago, but thankfully TPG Editor-at-Large Zach Honig did a great job breaking down the changes here.

If you’re trying to upgrade to United Polaris or domestic first class, you’ll need to find space in one of the following two fare classes:

  • PN – Global Services mileage and certificates, and all instant upgrades
  • PZ – Platinum and Premier 1K certificates and all mileage upgrade awards

Meanwhile if you’re looking to upgrade to United’s recently launched Premium Plus cabin, you’ll need space in the RN fare class, regardless of your elite status.

Unfortunately ExpertFlyer doesn’t currently support searching for two digit fare codes, so you’ll have to do your upgrade hunting directly with United. If you log in to your MileagePlus account and turn on “United Expert Mode,” you’ll be able to see a breakdown of available fare classes when searching for revenue flights, not award flights. You’ll note, unsurprisingly, that many of United’s longer and more premium flights are entirely zeroed out when it comes to upgrade inventory.

Delta Airlines

Delta comes last on this list because it offers the fewest options for upgrading your flights. Of course, even the lowest tier Silver Medallion elites are eligible for unlimited first class and Comfort+ upgrades on short- and medium-haul flights, but those are automatically requested and are processed based on your elite level (among other factors), so there’s not much you can do to increase your odds here.

Delta also recently eliminated mileage upgrades, meaning that the only traditional upgrade option left is using one of the carrier’s highly-exclusive Global and Regional Upgrade Certificates that upper-tier elites can select as a Choice Benefit. Diamond Medallion members can choose any of the following three combinations:

  1. Four (4) Global Upgrades
  2. Eight (8) Regional Upgrades
  3. Two (2) Global Upgrades and four (4) Regional Upgrades

Platinum Medallions can select four (4) Regional Upgrades as their one Choice Benefit for the year.

Unfortunately Delta doesn’t make it possible to search this upgrade inventory on the Delta app/website or through tools like ExpertFlyer, meaning that you’ll need to call Delta and play a good old-fashioned game of guess-and-check to find upgrade inventory.

Bottom Line

Clearing an upgrade to first or business class — especially before a long-haul, international flight — requires the perfect combination of luck and skill. The first thing you should do is look at the specific rules of the upgrade you’re trying to use to make sure your ticket is eligible (especially if you booked an award ticket or a basic economy fare). Next, you need to identify your airlines fare bucket for upgrade inventory in order to see if you’ll be able to clear in advance. Finally, leverage the above tools and strategies to maximize your chances at riding up front.

Thanks for the question, Jake, and if you’re a TPG reader who’d like us to answer a question of your own, tweet us at @thepointsguy, message us on Facebook or email us at

Featured photo by JT Genter / The Points Guy

Chase Sapphire Preferred® Card

WELCOME OFFER: 80,000 Points


CARD HIGHLIGHTS: 2X points on all travel and dining, points transferrable to over a dozen travel partners

*Bonus value is an estimated value calculated by TPG and not the card issuer. View our latest valuations here.

Apply Now
More Things to Know
  • Earn 80,000 bonus points after you spend $4,000 on purchases in the first 3 months from account opening. That's $1,000 when you redeem through Chase Ultimate Rewards®. Plus earn up to $50 in statement credits towards grocery store purchases within your first year of account opening.
  • Earn 2X points on dining including eligible delivery services, takeout and dining out and travel. Plus, earn 1 point per dollar spent on all other purchases.
  • Get 25% more value when you redeem for airfare, hotels, car rentals and cruises through Chase Ultimate Rewards®. For example, 80,000 points are worth $1,000 toward travel.
  • With Pay Yourself Back℠, your points are worth 25% more during the current offer when you redeem them for statement credits against existing purchases in select, rotating categories.
  • Get unlimited deliveries with a $0 delivery fee and reduced service fees on eligible orders over $12 for a minimum of one year with DashPass, DoorDash's subscription service. Activate by 12/31/21.
  • Count on Trip Cancellation/Interruption Insurance, Auto Rental Collision Damage Waiver, Lost Luggage Insurance and more.
  • Get up to $60 back on an eligible Peloton Digital or All-Access Membership through 12/31/2021, and get full access to their workout library through the Peloton app, including cardio, running, strength, yoga, and more. Take classes using a phone, tablet, or TV. No fitness equipment is required.
Regular APR
15.99%-22.99% Variable
Annual Fee
Balance Transfer Fee
Either $5 or 5% of the amount of each transfer, whichever is greater.
Recommended Credit

Editorial Disclaimer: Opinions expressed here are the author’s alone, not those of any bank, credit card issuer, airlines or hotel chain, and have not been reviewed, approved or otherwise endorsed by any of these entities.

Disclaimer: The responses below are not provided or commissioned by the bank advertiser. Responses have not been reviewed, approved or otherwise endorsed by the bank advertiser. It is not the bank advertiser’s responsibility to ensure all posts and/or questions are answered.