Top U.S. Airlines for 2024

With summer travel now in full swing, it’s time to announce TPG's Best Airline for 2024—alongside school vacations, barbecues, and busy flights to Europe.

This year’s rankings emerge as summer travel is projected to hit its highest peak since 2019, potentially even a record high.

Countless Americans will be searching for airline tickets, weighing factors such as cost, service quality, reliability, and of course, frequent flyer points and miles.

Every traveler has unique preferences, yet one question stands out above the rest: Is there a single best airline in the U.S.? Which carrier meets all the key expectations of travelers?

Each year, we gather thousands of objective data points to assess which of the 10 largest U.S. airlines offers the best combination of reliability, cost, service, and overall value. Our aim is to provide a fair and impartial evaluation of how these airlines perform for the average traveler.

The analysis for this year is complete, and we’re excited to share the findings. Read on to discover how your airline ranked in this year's assessments.

Top U.S. Airlines for 2024

1. Delta Air Lines
2. Alaska Airlines
3. United Airlines
4. American Airlines
5. Southwest Airlines
6. JetBlue
7. Hawaiian Airlines
8. Allegiant Air
9. Spirit Airlines
10. Frontier Airlines

Continue reading for our comprehensive analysis and methodology — and find out what allowed Delta to secure the top spot in our rankings for the sixth consecutive year.

Overall Rankings and Key Insights

Here’s a brief overview of this year’s overall scores, highlighting the best and worst-performing categories for each airline. Last year’s rankings are included in parentheses for reference.

* All data pertains to the 12-month span from January 1 to December 31, 2023, except for customer satisfaction. Due to a reporting delay as the U.S. Department of Transportation updates its methodology for tracking complaints, this information is only available for the five-month period from January 1 to May 31, 2023.

Key insights from this year’s analysis include:

• Delta secures the top spot for the sixth consecutive year. The Atlanta-based airline once again achieved the highest ranking, notably excelling in timeliness, though it was the leading airline in only that category. Delta also tied with Allegiant in the involuntary bumps category. Despite not being the most affordable, its consistent performance across other categories led it to be the overall winner.
• No major surprises compared to last year. Alaska and United traded places, as did JetBlue and Hawaiian, along with Allegiant and Spirit. No airline experienced significant movement, indicating stability and a continued recovery from the disruptions of the post-pandemic period.
• Some airlines showed improvement over 2022, while others declined. A few airlines saw slight decreases in their scores: Delta (-0.57), United (-1.57), Hawaiian (-5.80), Spirit (-4.44), and Frontier (-5.39). Meanwhile, Alaska (+3.84), American (+1.01), Southwest (+2.25), JetBlue (+1.70), and Allegiant (+6.32) improved their overall scores, though none shifted more than one spot in the rankings.
• Consumer complaint data is not the full picture. The U.S. Department of Transportation usually reports a variety of metrics with a three-month delay. However, they postponed the release of customer complaints due to a surge in complaints compared to pre-pandemic levels. Consequently, the customer satisfaction score does not account for passenger experiences during the latter part of the year, including the peak summer and holiday travel seasons.

Curious about how these airlines ranked? Continue reading for an in-depth examination of each category used in our rankings, along with the weight assigned to each. The complete methodology can be found at the end of the report.

Top U.S. Airlines for Reliability

Many factors contribute to the overall air travel experience, starting from the flight search to collecting your luggage and exiting the airport. Ultimately, an airline’s primary responsibility is to transport you to your destination as promised and on schedule.

For this reason, operational reliability carries the most weight in our rankings, comprising 30% of our overall analysis. We evaluate five factors that fall under the category of reliability:

• Timeliness: The frequency of flight delays for the airline
• Cancellations: The rate at which flights were canceled by the airline
• Bumps/involuntary denied boardings: The instances of travelers being bumped from oversold flights
• Baggage: The frequency of mishandled checked luggage by the airline
• Wheelchairs/scooters: The rate at which mobility devices were mishandled

The results yielded an unexpected winner: Allegiant. It achieved the highest scores across the five metrics of this category. The complete reliability rankings are as follows:

1. Allegiant
2. Delta
3. Alaska
4. Southwest
5. Hawaiian
6. United
7. American
8. JetBlue
9. Spirit
10. Frontier

While ultra-low-cost carriers like Allegiant, Spirit, and Frontier are often viewed as less reliable and lacking in onboard experience, Allegiant's 2023 reliability score challenges this perception, marking it as the best in the industry. Despite ranking seventh in on-time performance, Allegiant excelled in the other four reliability metrics.

Among the 10 airlines we assessed, Allegiant had the fewest flight cancellations, with just 782 out of 115,539 flights cut in 2023 (0.68% cancellation rate). Alaska followed closely, canceling 2,849 out of 385,945 flights (0.74%). In contrast, Frontier canceled 3,774 of its 177,542 scheduled flights (2.13% cancellation rate).

Allegiant achieved the highest score for involuntary bumps, with an impressive rate of zero, tying with Delta.

In stark contrast, Frontier ranked as the worst performer, denying boarding at a staggering rate of 35.06 per 100,000 passengers, totaling 10,123 out of 28,872,300 travelers. For comparison, American Airlines followed with 5.57 involuntary denials per 100,000 passengers.

Allegiant is clearly excelling in its baggage handling as well. While they don’t offer free checked bags and charge for carry-ons with the base fare, Allegiant reported the fewest lost or damaged bags, with only 1.89 mishandled bags per 1,000 checked. In contrast, American had the highest rate, with 7.61 mishandled bags per 1,000.

Allegiant's strong performance extended to wheelchairs and mobility scooters, too. The Las Vegas-based airline mishandled checked wheelchairs at a rate of just 0.37 per 100. Spirit, however, had the highest mishandling rate, at 5.35 per 100 checked wheelchairs.

Top U.S. Airlines for the Travel Experience

While reliability matters, many individuals primarily consider the onboard experience when evaluating the 'best airline.' For a lot of travelers, the quality of snacks, meals, or entertainment can significantly influence their journey.

At TPG, we also value the travel experience, assigning it a weight of 25% in our overall rating, just trailing behind reliability. The travel experience assessment examines four key elements:

• Cabin features: This includes what you can expect during your flight, such as Wi-Fi availability, seat comfort, and inflight entertainment options.
• Lounges: The extent and accessibility of an airline's lounges, as well as their affordability.
• Family: The extent to which an airline accommodates families traveling with children.
• Customer satisfaction: The frequency of passenger complaints lodged with the DOT regarding the airline.

Alaska Airlines emerged as the overall leader, with the complete rankings for the category as follows:

1. Alaska
2. Delta
3. American
4. United
5. JetBlue
6. Hawaiian
7. Southwest
8. Spirit
9. Allegiant
10. Frontier

In terms of cabin features, JetBlue takes the lead again, just as it did last year and the year before. This New York-based airline excels thanks to its provision of free Wi-Fi on all flights, alongside seatback entertainment screens and the largest average economy seat size among U.S. carriers.

Alaska Airlines stood out for its domestic lounges, an essential factor for many frequent travelers. Although the airline operates only nine lounges, its Alaska Lounge+ members enjoy access to numerous additional lounges across the U.S., including over 40 American Airlines Admirals Clubs, various United Club locations, and several third-party lounges.

Alaska also achieved the highest rating for customer satisfaction, although it’s worth noting that complaint data was only gathered for the initial five months of the previous year. Additionally, the airline ranked first for family travel experiences, taking into account factors like early boarding, baggage fees, onboard snacks, and inflight entertainment options.

It's perhaps expected that ultra-low-cost airlines ranked lowest in overall experience. Their scores suffered due to cramped seating arrangements, additional fees—impacting family experience ratings—and the absence of lounges.

Top US airlines for affordability and coverage

Before considering reliability or travel experience, it's essential to determine which airlines fly to your desired destination and what the ticket prices will be.

In our cost and reach category, we analyze which airlines offer the best combination of pricing and network coverage. This includes evaluating airfare costs and common additional fees. Our assessment also measures the extent of each airline's domestic route network. This category accounts for 20% of the overall score and encompasses three key factors:

• Route network: The number of domestic airports served by an airline
• Affordability: The distance you can travel for the price you pay, based on financial data from the Bureau of Transportation Statistics
• Ancillary fees: The typical costs incurred by passengers for baggage and change/cancellation fees

The cost and reach category offers some intriguing insights. While ultra-low-cost airlines are undoubtedly the most budget-friendly, they also impose significant ancillary fees—often multiple ones. Additionally, their route networks are typically smaller compared to legacy carriers.

Which airline achieves the best balance? Here are our findings:

1. Southwest
2. United
3. American
4. Delta
5. Alaska
6. Allegiant
7. Spirit
8. Hawaiian
9. JetBlue
10. Frontier

It’s no surprise that Southwest takes the top spot. Although it serves roughly half the number of domestic cities compared to the three largest legacy airlines—American, Delta, and United—it still boasts a substantial route network. This is particularly evident when juxtaposed with other low-cost carriers like Spirit and Frontier, as well as JetBlue, which focuses on the East Coast, and Alaska, which targets the West Coast.

Southwest's notable edge lies in its fee structure. The airline does not impose change or cancellation fees. Although other major airlines have significantly reduced these fees from pre-pandemic levels, they still tend to charge more on average for 'extra' costs than Southwest did in 2023.

Southwest is well-known for allowing two free checked bags for each passenger. If travelers check in more than two bags, they incur extra charges, so Southwest did generate some revenue from baggage fees in 2023. However, this amount was only a small portion of what other airlines collected.

In 2023, Southwest averaged just 43 cents in fees for each passenger carried. This is considerably lower than the fees collected by American, Delta, and United, which ranged from $6 to $9 per passenger for baggage. Southwest fared even better when compared to ultra-low-cost carriers, which compensate for lower ticket prices with numerous add-on fees. Spirit and Allegiant averaged just under $27 in fees per passenger, while Frontier collected an impressive $40 for every passenger flown.

If you can travel light and steer clear of extra charges, budget airlines remain the most economical option. Frontier generated $118 in fare revenue for every 1,000 domestic miles flown per passenger, with Spirit close behind at $118.13. Allegiant followed at a more distant $159.38.

As expected, legacy airlines were the most expensive. Delta ranked lowest in our affordability assessment, averaging $302.50 in fare revenue per 1,000 passenger miles flown. American followed at $279.03, while United was the most affordable among the 'Big Three' carriers at $261.76. Southwest, positioned between legacy and low-cost carriers, came in at $191.74.

Top US airlines for loyalty

The last category in our rankings focuses on loyalty—an important subject for both TPG staff and readers. We assigned a weight of 25% to this category, which includes two key factors:

• Frequent flyer program: The value of an airline's loyalty program, assessed based on TPG's valuations, elite status offerings, cobranded credit cards, partner airlines, and expiration policies
• Award availability: The ease and value of redeeming rewards during popular travel periods

As in the previous year, United ranked first. Here are the complete results:

1. United
2. American
3. Alaska
4. Delta
5. JetBlue
6. Southwest
7. Hawaiian
8. Spirit
9. Frontier
10. Allegiant

The competition at the top was intense, but United emerged with the highest rating for rewarding frequent flyers. The airline boasts the largest number of partners for earning and redeeming points, along with four consumer credit cards. American closely followed in second place, with Alaska in third.

Delta, last year's second-place finisher, dropped to fourth. This decline can be attributed to its high mileage costs for award flights and recent changes to its elite status program that many frequent flyers have criticized.

Low-cost carriers generally struggled in this category, facing challenges due to their limited partnerships, fixed or low value for miles, poor award availability, and/or restrictive expiration policies for points.

Methodology

TPG's Best Airline rankings are derived from scores across four major categories, each comprising multiple criteria. All data for the 2024 report pertains to flights conducted within the 12-month period from January 1 to December 31, 2023.

Here is a detailed overview of the methodology and the data sources used:

Reliability (30%)

• Timeliness (based on delayed flight data from the DOT)
• Cancellations (based on canceled flight data from the DOT)
• Involuntary bumps (based on data on involuntary denied boardings from the DOT)
• Baggage (based on mishandled baggage data from the DOT)
• Wheelchairs/scooters (based on mishandled baggage data from the DOT)

Experience (25%)

• Cabin features (sourced from SeatGuru and each airline's inflight amenity information)
• Lounges (based on the number of lounges, cities served, and membership costs for each lounge network)
• Family travel (rated on a 0-to-5 scale considering boarding processes, perks, and onboard food/entertainment)
• Customer satisfaction (derived from customer complaint data reported to the DOT)

Cost and reach (20%)

• Route network (using the monthly average of domestic cities each airline services, sourced from the DOT)
• Affordability (based on financial statistics from the BTS)
• Baggage/change fees (using financial data from the BTS)

Loyalty (25%)

• Frequent flyer program (analyzed using our monthly valuations, elite status updates, and each airline's website)
• Award availability (based on real-time reward inventory for popular domestic routes across three different periods)

For each criterion, raw data scores were transformed into scaled scores ranging from zero to ten. Typically, the lowest-performing airline received a score of zero, while a score of ten was assigned to an airline deemed 'perfect' when possible. For instance, both Allegiant and Delta earned a score of 10 for involuntary bumps since they recorded zero (or virtually zero) incidents last year.

In instances where perfection was not easily defined, the top-performing airline received a score of 10.

By employing scaled scores instead of a straightforward ranking system, we effectively 'graded' each airline in relation to the others. Each airline's score for specific criteria reflected how much better it performed compared to the lowest-scoring carrier.

For example, Alaska recorded the fewest complaints filed with the DOT during the first five months of the year, closely followed by Delta (2.94 complaints per 100,000 passengers compared to Delta's 3.70).

We normalized these figures by comparing them against the lowest-performing airline (Frontier, which had 38.76 complaints per 100,000 passengers) and the ideal score (0 complaints per 100,000 passengers). This conversion resulted in scaled scores of 9.24 out of 10 for Alaska and 8.09 out of 10 for Delta.

Each individual score was then adjusted according to the specified weights to calculate the final cumulative score presented in the table.

Final thoughts

Selecting a flight and an airline for your upcoming journey involves various factors. While price is important, reliability, the rewards you can earn, and the overall passenger experience also play crucial roles. Naturally, no single airline can cater to every traveler's needs, meaning the significance of each factor varies among individuals.

Nonetheless, our report relies on objective data and equitable weighting that we believe provides a comprehensive overview for a diverse group of travelers.

For the sixth consecutive year, Delta has been awarded the title of TPG's Best Airline for 2024.

Delta's success demonstrates that excelling in every category isn't always necessary. What matters more is delivering strong performance across various areas and standing out by providing a dependable and consistent service overall.

Despite alienating some frequent flyers with adjustments to its rewards program and having the highest fares in the U.S. according to our analysis, Delta's reliability, performance, features, and overall experience collectively help it maintain its leading position.