How to get an upgrade when flying on major US airlines

Upgrading to a better seat for your next flight may be high on your wish list. Whether you want a little extra legroom or to experience a truly better class of service, upgrading your flight can be complicated. Not only do upgrades work differently for each airline, but there are also multiple ways to score an upgrade with some airlines.

To help you understand how to get upgraded to first class, or perhaps just a better seat, here's a list of our airline-specific upgrade guides:

• Allegiant Air upgrade guide.
• American Airlines upgrade guide.
• Delta Air Lines upgrade guide.
• Frontier Airlines upgrade guide.
• Hawaiian Airlines upgrade guide.
• JetBlue Airways upgrade guide.
• Southwest Airlines upgrade guide.
• Spirit Airlines upgrade guide.
• United Airlines upgrade guide.

These airline-specific guides give you a lot to compare. Even if a free upgrade isn't possible for your flight, there may still be ways to snag an inexpensive upgrade. So, here are some suggestions on how to get an upgrade to first class, an exit row or a seat with more legroom.

Use your miles for free upgrades on flights

When flying many major airlines, you can use your miles to upgrade. But, every airline handles upgrades with miles a little differently. Some, like American and United, charge a co-pay on most mileage upgrades (though United waives the co-pay for elite members). Meanwhile, Delta offers mileage upgrades at a fixed rate of about 1.07 cents per mile.

In some situations, the number of miles required to upgrade your seat is significantly less than what you might need to redeem for an award flight. Redeeming miles for an upgraded seat can be a great use for your miles if you only have a small mileage balance with an airline.

Redeeming miles for upgrades can also be a great use of transferable currencies such as Bilt Rewards or Chase Ultimate Rewards since you can transfer the amount you need to top off your account.

Related: How to upgrade to first class without using a ton of cash

Consider a bundle for a free upgrade

Once you wade into the world of low-cost airlines, you'll find that you can select better seats on them as part of purchasing a bundle. Purchasing a bundle just for a seat with extra legroom is seldom a good idea. But, if you were planning to check a bag or wanted priority boarding, you may find that purchasing those items a la carte is more expensive than purchasing a bundle of add-ons.

Frontier's "The Works" bundle includes items such as a carry-on bag and a checked bag and allows you to select any seat on the plane, including seats with extra legroom. Allegiant and Spirit offer similar bundles, though Spirit sells its unique Big Front Seat separately. When considering a low-cost carrier, think about the add-ons you might purchase and how that decision might help you get a cheap or free upgrade to a better seat.

Related: ’Til death — or a first-class upgrade — do us part: Testing wedding vows at 35,000 feet

Take advantage of elite status for a free upgrade

In the 1990s and 2000s, it was typical for domestic first-class cabins on American, Delta and United to mostly seat business travelers with elite status. In those days, that was how to get free upgrades on flights.

Over time the airlines turned the dials of yield management to make money off those seats they were giving away for free. First-class seats sell for a lot less money today than in decades past. Airlines now fill their first-class seats primarily with customers who booked a first-class fare.

However, there are still plenty of opportunities for a free upgrade to first class. This is especially true if you fly unpopular routes or fly at non-peak times. You can also increase your chances of finding a free upgrade by using services like Expert Flyer (owned by TPG’s parent company, Red Ventures) to scan for flights with a greater chance of an upgrade.

There are many reasons it can be better to have top-tier elite status on one airline versus mid-tier status on multiple airlines. Upgrades are one of these areas, since the upgrade waitlist is organized by status level.

Related: Here’s how to use airline miles for a first class upgrade

Pay for the seat you want

Many business travelers begrudgingly admit a new mantra is in play when it comes to airline travel: "Buy the seat you want." It's an acknowledgment that complimentary upgrades are harder to come by than ever and someone else is often willing to pay for the first-class or exit row seat you used to get for free.

Luckily, a few credit cards offer annual travel credits you can use to reduce your out-of-pocket costs. Chase Sapphire Reserve is a good example, with a very easy-to-use $300 travel credit per account anniversary year. To a lesser degree, the Capital One Venture X Rewards Credit Card is another option with its up to $300 travel credit, but you must use the credit through the Capital One travel portal.

Related: How to upgrade from economy to premium economy without breaking the bank

Bottom line

If more comfort is important to you the next time you take to the air, make sure you do your research before purchasing a ticket. Across all the major domestic U.S. airlines, you'll find a wide range of upgrade procedures. So, learn about airline upgrade policies and procedures before clicking the purchase button for your next flight.