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How Can I Tell When Airlines Have Available Upgrade Space?

April 23, 2019
6 min read
How Can I Tell When Airlines Have Available Upgrade Space?
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"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 ...

[pullquote source="TPG READER JAKE"]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?[/pullquote]

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.

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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 image by The business-class cabin on AA's 787-9.