A new report ranked US airlines ranked worst to best using several metrics — see how they stacked up against each other

• Finance website WalletHub revealed the best and worst US airlines based on data from the Department of Transportation.
• Delta Air Lines took the top spot, scoring high in terms of reliability, comfort, and customer satisfaction.

Personal finance website WalletHub revealed the best airlines in the US based on 2021 flight data collected from the US Department of Transportation.

The company ranked 11 carriers from best to worst, including mainline airlines like American and Southwest, and low-cost carriers like Spirit and Frontier.

Two regional carriers — SkyWest Airlines and Envoy Air — were included because they make up at least 1% of domestic scheduled service and report data to the DOT, according to the company.

WalletHub scored each airline based on 16 metrics across four main categories, including baggage, departures, and complaints, animal-related incidents, inflight comfort, and safety. Subcategories included factors like delays, WiFi availability, legroom, denied boardings, and price.

While price is a common dealbreaker for many consumers, WalletHub noted that its report examines "overlooked aspects of air travel" to help travelers "make more informed decisions." However, the company said "for the sake of fairness," it considered costs "in relation to inflight amenities."

"For example, it wouldn't be right to penalize an airline that charges for drinks if its tickets are far cheaper than those from an airline with free in-flight refreshments," it explained.

WalletHub took each airline's score from the four major categories to determine the overall best and worst carriers in the US. Scores were based on specific criteria, like the rate of delays or the number of customer complaints.

Then, the company totaled the points from each category to give an overall performance rank. Delta earned the highest score of 70.48 out of 100, while Southwest came in last with just 30.60 points earned.

WalletHub disclosed that each metric was allowed a maximum number of available points an airline could earn and that the weight of each and its calculation into the overall score was based on the company's subjective view. However, it said points were generally allocated "based on common sense."

In addition to ranking the best airline, the company also gave six other awards, including cheapest airline, safest airline, most reliable airline, the best airline for pets, least complained-about airline, and most comfortable airline.

Delta took home the most medals, including being the best overall US airline, the most reliable, and tied for the safest for animals. Meanwhile, JetBlue and Frontier earned top spots for comfort and affordability, respectively.

Here's a closer look at WalletHub's best and worst US airlines, and the individual awards each received.

11. Southwest Airlines

Southwest ranked last on WalletHub's list, bringing up the rear in several categories, including being the least reliable and the least safe airline. WalletHub gave Southwest a score of 7.84 out of 50 for reliability, whereas the top performers, including Delta and Hawaiian, scored above 30.

The data also showed Southwest's reliability tanked in comparison to the year prior, which earned a score of 26.80. This is likely, in part, due to the airline's multi-day meltdown in October 2021 that left thousands of passengers stranded.

The airline got its low safety rating due to an uncontained engine failure in 2018 that resulted in the death of a passenger, which forced WalletHub to deduct points.

10. American Airlines

American ranked second-to-last on WalletHub's list, earning low scores in reliability, price, and safety. According to the data, the carrier sustained at least 50 passenger or employee injuries that required medical care in 2021, causing its low safety rating.

Meanwhile, the carrier earned a reliability score of 14.24, though it did earn a higher comfort score of 4 out of 5.

9. JetBlue Airways

JetBlue was named the worst US airline by the Wall Street Journal earlier this year due to poor on-time performance and a high number of passenger complaints.

WalletHub's data reared similar results, scoring its reliability at 16.52 out of 50, as well ranking fourth in terms of customer complaints.

However, not all is bad for JetBlue. The carrier was ranked the best airline for onboard comfort, including offering free amenities like WiFi, inflight entertainment, snacks, and beverages. The carrier also offers the most legroom in economy, Conde Nest Traveler reported.

8. Frontier Airlines

Frontier ranked low in terms of reliability, with a score of 13.18, and came in last for comfort due to a lack of inflight amenities, like WiFi or free snacks and drinks.

The carrier also configures its planes with 28 inches of legroom, which is the lowest offered in the US, according to travel magazine AFAR.

However, Frontier did earn the top ranking for affordability, offering consumers the cheapest plane tickets of any other carrier. The data showed Frontier's airfare averaged 3.53 cents per mile.

7. United Airlines

While United ranked low compared to other carriers, it received the third-best reliability score of 26.67 out of 50 and a high comfort score of 4.5 out of 5.

However, its low overall ranking can be contributed to its high number of passenger complaints. According to DOT data, United had 3,581 complaints in 2021, which came out to 29.73 complaints per 100,000 passengers, WalletHub revealed.

6. SkyWest Airlines

Regional carrier SkyWest, which flies on behalf of United, Delta, American, and Alaska, earned high rankings for pet-friendliness and customer satisfaction. Specifically, the carrier received 328 complaints in total, according to DOT data, giving it a rate of 0.92 complaints per 100,000 passengers.

Because Skywest flies for four carriers, WalletHub used the average maximum and minimum scores for each situation to determine the regional carrier's overall comfort score.

5. Spirit Airlines

Rounding out the top five carriers, Spirit Airlines performed well in 2021 in terms of affordability and safety.

The carrier is the second-cheapest airline behind Frontier, with an average airfare of 3.82 cents per mile. Meanwhile, the airline received a score of 19.99 out of 50 for reliability, which is average compared to other airlines.

Like Frontier, Spirit did rank low in onboard comfort, offering no free amenities inflight, except for a seat and a personal item.

4. Envoy Air

Envoy is a wholly-owned subsidiary of American and is one of the top-performing operators, according to WalletHub. The airline earned an overall score of 60.46 out of 100, which is double Southwest's score of 30.60. It also scored high for pet safety.

However, Envoy was the most expensive carrier of 2021, with an average fare of 12.42 cents per mile. This can mostly be attributed to the carrier flying on behalf of American to small markets that have higher operating costs, causing airfare to increase.

3. Alaska Airlines

Alaska is the third-best airline in the US, according to WalletHub. The airline earned the title of the safest airline and scored high in terms of reliability, comfort, and price.

The airline scored 4.5 out of 5 for comfort, tying with Delta and just losing out to JetBlue.

2. Hawaiian Airlines

Hawaiian is the runner-up this year, scoring high in affordability, reliability, and safety. However, the airline only beat out Spirit and Frontier in terms of comfort, scoring 2 out of 5.

Meanwhile, the airline had the second-highest number of passenger complaints with 37.63 per 100,000 passengers, according to WalletHub data. The airline received an overall high score due to its strong on-time performance and safety.

1. Delta Air Lines

Just like the Wall Street Journal, WalletHub named Delta the best airline in the US. The Atlanta-based carrier is the most reliable airline and came in second for comfort, tieing with Alaska, Southwest, and United.

The airline has also proved its responsibility with pets, reporting no animal-related incidents in 2021. Moreover, the airline had one of the lowest rates of consumer complaints, receiving 1.92 complaints per 100,000 passengers, according to WalletHub data.