Cheapest Airlines in the US - Budget Carrier Rankings 2024

Written By Amy Lancelotte

10 minutes read
Last Updated: October 15, 2024

Flights can be one of the more expensive components of any trip, so it’s useful to know the cheapest airlines in the US if you need to save money. It’s not surprising that most of the budget carriers we reviewed rank higher on our list, meaning they have lower total passenger revenue per seat mile. 

• The US airlines we reviewed made over $2 trillion in passenger revenue in 2022 and 2023.
• These 10 airlines had over 1 quadrillion seat miles available each year.
• The average revenue for airlines per seat mile in both years ranged from $0.0985 to $0.1761.

Let’s get to our AirAdvisor list of the cheapest US-based airlines to fly in 2024 and explore the outliers. To form our top 10 list we averaged out the revenue per available seat mile for each carrier in 2022 and 2023. Some airlines billed as low-cost don’t rank as well as you might think.

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Top 3 Cheapest Airlines in the US

#1 Frontier Airlines

What is the cheapest airline in the US? Based on our research, Frontier Airlines has the lowest total passenger revenue per seat mile of the 10 airlines we reviewed. Their number of $0.0985 per seat mile seems low, in fact, they all do. But think about how many actual miles your plane is flying. Costs can definitely start to mount up.

Frontier Airlines is often referred to as an ultra-low-cost carrier, and this certainly rings true based on our research. US airlines don’t get any cheaper than this as a whole. For destinations in the US, Central America, and Mexico, check with them first - they are more than $0.01 per mile cheaper than the next airline.

#2 Spirit Airlines

The second-cheapest airline on our list is Spirit Airlines, another ultra-low-cost carrier that flies throughout the US, the Caribbean, and Latin America. As for their total revenue per available seat mile - that’s $0.1110, which, as mentioned, is more than one cent above our number 1 cheapest airline.

Spirit Airlines is known for promoting the “Bare Fare,” which is simply a charge for your seat and one personal item. There are no frills with Spirit, but that means it’s much easier to keep your overall flight cost low.

#3 Hawaiian Airlines

In the third place spot, we start to see some anomalies. Hawaiian Airlines is not considered a low-cost carrier in the technical sense, although their AirAdvisor Cheapest Airline Score might beg to differ. As the highest-ranking non-budget airline, Hawaiian Airlines’ seat mile revenue average for both years was $0.1236 - another full cent above Spirit Airlines.

Hawaiian Airlines is an ideal choice for travel to and from Hawaii from Asia, the South Pacific, and of course, North America. If you’re planning a trip that involves the Aloha State in any way, Hawaiian Airlines is often a cheap option.

Plus, based on our overall research, Hawaiian Airlines is by far the best combination of reliability and price of any airline we reviewed. You can also dive into the Most Reliable Airlines in the US if reliability is a crucial factor for you.

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How the Others Stack Up - Spots 4 Through 10

#4 Allegiant Air

In the number 4 spot, we have Allegiant Air, which, unsurprisingly, is another ultra-low-cost airline. Allegiant’s revenue per seat mile is a whole $0.03 more than Frontier’s and averaged $0.1294 for 2022 and 2023 combined.

Allegiant Air is still a good option for budget-conscious travelers and remains one of the cheapest domestic airlines, but this airline only flies within the US. Zero international destinations are available currently, and the best they can do is get you near (not to) Canada.

#5 JetBlue

The fact that JetBlue is a low-cost airline (not ultra) means its position after the top 3 makes sense. It’s just a little surprising that Hawaiian Airlines ranks two spots above this so-called budget-friendly carrier.

In 2022, JetBlue’s total revenue per seat mile was $0.1332, and in 2023, it was $0.1315. This averages out to $0.1324, and after this, we start to see a big jump in price as we leave the true budget airlines behind.

#6 Alaska Airlines

After Hawaiian Airlines, Alaska Airlines is the next cheapest non-budget airline in the US. The carrier offers domestic flights and flights from US cities to Canada, Mexico, Costa Rica, Guatemala, The Bahamas, and Belize. Their average revenue per seat mile is $0.1554, which puts them above the overall average of the 10 airlines of $0.1438.

Although Alaska Airlines is above the mid-range of our cheapest airlines, don’t immediately rule them out. The company offers flash sales throughout the year, so it’s worth checking their prices, especially if you want to avoid a no-frills budget airline.

#7 United Airlines

At $0.1650 per seat mile, United Airlines is certainly not the cheapest airline out there, but it is the top major US airline to appear in the rankings. Although fares may be higher than average with United, the airline offers extensive routes throughout the world, more specifically to the 6 inhabited continents. 

If you’re planning to fly long distances, United is a solid option that will balance price and comfort.

#8 American Airlines

Almost another cent higher per seat mile than United, American Airlines, at number 8, is definitely one of the pricier carriers you can choose. Their 2022 and 2023 revenue per seat mile averages out to $0.1730 and is not far off the last two entries on our list.

American Airlines is another of the US’ major carriers with an enviable selection of routes. If you need to get somewhere on a certain day at a certain time, check out the fares with American, as the flights are frequent, and over 350 destinations in 60 countries are available.

#9 Southwest Airlines

Although Southwest Airlines is technically the world’s largest low-cost carrier, the airline’s total revenue per seat mile is one of the highest on our list at $0.1732. So, travelers who think that Southwest offers the lowest prices are in for a surprise. This brings forth the question of whether Southwest should even be considered a budget carrier. 

That being said, at least part of the reason for Southwest’s higher prices is that they don’t just offer customers the basic seat and one personal item. There are additional fare categories that include things like seat selection, checked bags, and upgraded seats, which will inevitably drive up the revenue per seat mile.

#10 Delta Airlines

Delta Airlines is the most expensive of our 10 airlines with a revenue per seat mile of $0.1761. As an airline, Delta has many strengths, but price isn’t one of them.

Delta offers flights all over the world, so there is a place for them on the itinerary of even the most budget-conscious traveler. Their website has a section for current flight deals, and you can subscribe to their newsletter to be informed whenever new sales are starting.

Delta is among the most reliable airlines we reviewed, which might help explain their higher prices. If you are one of the unlucky ones and experience an interruption on a Delta flight (or a flight from any other airline), we can help. It’s often possible to claim compensation for delayed flights and instances of denied boarding.

Cheapest International Airline in the US

Determining the cheapest international airline is easy if you take “international” in the truest sense of the word. Of the airlines that fly to any country other than the US, the cheapest airline would be the same as our overall winner - Frontier Airlines. They fly to the Caribbean, Mexico, and Central America. But, in truth, their destinations are quite limited.

For anyone searching for the cheapest international airline that flies to destinations like Asia, Europe, South America, and Africa, the frontrunner is United Airlines. Some other airlines fly to one or two of these destinations, but United Airlines is the cheapest carrier that has multiple flights throughout North America and 5 other continents.

AirAdvisor US Airline Affordability Rating - Top Carriers Ranked

Comparison: 2022 vs 2023

Since we have data for both 2022 and 2023, we thought it would be useful to see which airlines’ revenue per seat mile increased year on year and which ones actually went down.

Our comparison reveals mixed results in that half of the airlines decreased in revenue per available seat mile in 2023 compared to 2022 and the other half increased. The highest increase was with Allegiant causing the airline to drift from third place in 2023 to fourth place in 2024.

Our Data

To determine the cheapest airlines in the US, our methodology was fairly simple. We looked at each airline’s publicly available balance sheet for 2022 and 2023. We used the total passenger revenue per seat mile that they published to rank them, averaging out both years. The lower the dollar amount, the higher the ranking.

Conclusion

Many things go into determining the ideal airline for your next business trip or vacation. If you’d like an overall view of these same 10 airlines and how they rate in 9 different categories, including cost, check out our post on the Top 10 Airlines in the US.

Our AirAdvisor Cheapest Airlines Score should be used any time you are planning to book a flight. When cost is important to you, check with the highest-ranked airline that flies to your destination first and then expand out from there. Many factors can influence the cost of an individual flight, like when you book and when you fly, and airlines also offer sales and discounts when flights aren’t as full as they want. Keep this in mind, and use our rankings as a guide to start your search.

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