(The Hill) — Passenger complaints have soared as airlines canceled and delayed flights this year, but reliability has varied between airlines.

The Department of Transportation (DOT) released its latest air travel consumer report late last month, noting that roughly 24 percent of commercial flights between destinations in the United States did not arrive on time in the first half of the year. 

The figure is a 52 percent jump from the same period last year, although carriers operated fewer flights in 2021 as more Americans avoided flying out of concerns of catching COVID-19.

Travel demand has now resurged to levels not seen since before the pandemic, but the airline industry has struggled to meet the influx of passengers, facing issues like staffing shortages, severe weather and high fuel costs. Some airlines have also placed blame on labor shortages at the Federal Aviation Administration (FAA).

Here’s how airlines’ on-time arrival percentages ranked during the first six months of 2022:

1. Hawaiian Airlines: 82.14 percent

Hawaiian Airlines beat out other airlines for the top spot, with more than 8 in 10 of its scheduled U.S. flights arriving on time.

The airline is smaller than the other nine included in DOT’s analysis, and Hawaiian also outranked the other carriers last year.

About 91 percent of Hawaiian’s U.S. flights during the first six months of 2021 arrived on time.

“We are proud of our frontline teams and everyone supporting our operations for getting our guests to their destination on time and with aloha while maintaining our industry-leading punctuality record,” said Hawaiian Airlines spokesperson Alex Da Silva.

2. Delta Air Lines: 80.75 percent

Delta Air Lines and flights operated by regional carriers marketed under the Delta brand were ranked No. 2 in DOT’s report.

Flights operated by Delta itself slightly outpaced the on-time arrival percentage of its regional carriers. Just over 80 percent of U.S. Delta-operated flights arrived on time, about a percentage point higher than its codeshare partners.

Delta has touted its leading record in its promotional appeal to customers, saying on Wednesday it was prepared to carry up to 2.9 million passengers over the upcoming busy Labor Day travel weekend.

“We’re looking forward to welcoming our customers on board for Labor Day weekend,” Allison Ausband, Delta’s chief customer experience officer, said in a statement. “We’ve taken steps this summer to ensure our people have the tools and support they need to deliver on our high standards for reliability, while offering Delta’s signature customer service with warmth and care.”

3. Alaska Airlines: 78.91 percent

Alaska Airlines and its codeshare partners clocked in at No. 3 on the list, with just under 8 in 10 U.S. flights arriving on time during the first half of the year.

Flights branded as Alaska Airlines but operated by its regional partners, Horizon Air and SkyWest Airlines, arrived on time about 81 percent of the time, slightly more often than those operated by Alaska itself.

An Alaska Airlines spokesperson did not return a request for comment.

4. United Airlines: 76.92 percent

United Airlines’ on-time arrival percentage registered about two percentage points below Alaska, with 76.92 percent of U.S. United Airlines-marketed flights arriving on time in the first half of 2022.

The figure marks a dip from the same period in 2021, when 83.47 of the airlines’ marketed flights arrived on time. United similarly ranked No. 4 during that period when compared to the other carriers.

United achieved its highest second-quarter revenue in the company’s history this year, which was also the airline’s first profitable quarter since the start of the pandemic.

A United Airlines spokesperson did not return a request for comment.

5. American Airlines: 76.75 percent

American Airlines, which marketed more flights than any other carrier in the first half of the year, clocked in near the middle of the pack, barely behind United Airlines.

Like United, a slight majority of flights marketed by American Airlines were operated by the carriers’ regional partners.

Those regional carriers’ flights arrived on time 78.01 percent of the time, compared to 75.33 percent of those operated by American Airlines.

Pilot unions at three regional carriers wholly owned by American Airlines — Envoy Air, Piedmont Airlines and PSA Airlines — recently announced contract agreements that include significant pay increases as part of their efforts to attract and retain pilots.

6. Southwest Airlines: 73.87 percent

Just under 74 percent of Southwest Airlines flights arrived on time in the first half of the year, earning the carrier sixth place out of the 10 airlines assessed by DOT.

As the industry faces scheduling snafus in part due to labor shortages, the airline said in a statement that it has grown its full-time equivalent employee base to more than 62,000, which is higher than its number of employees at the end of 2019.

“While on-time performance through June was down, our flight completion factor has recently been among the highest in the industry,” the airline said.

Most other major carriers use a hub-and-spoke system in which airlines concentrate flights in a handful of central airports. But Southwest is one of a few exceptions, instead leveraging a point-to-point strategy that offers direct flights between many smaller airports.

7. Spirit Airlines: 69.31 percent

Roughly 7 in 10 Spirit Airlines flights arrived on time between January and June, placing the low-cost carrier at No. 7 in DOT’s ranking.

When reached for comment, a Spirit Airlines spokesperson pointed to the company’s statement last month indicating its operational performance ranked among the industry best in the two months after Spirit’s peak summer schedule went into effect on June 5.

“These great results are among the best in the industry and are due to the relentless dedication of our Spirit family,” John Bendoraitis, the company’s chief operating officer, said in the statement. “Our team rose to the occasion to serve record numbers of summer travelers and work through industry challenges to deliver a high value experience for our guests.” 

8. Frontier Airlines: 64.50 percent

More than a third of Frontier Airlines flights did not arrive on time, according to DOT.

About 81 percent of Frontier’s flights arrived on time during the first half of 2021.

The airline is one of the country’s smaller commercial carriers, marketing the third-lowest number of flights out of the 10 assessed by DOT, with only Hawaiian and Spirit airlines marketing fewer flights.

A Frontier Airlines spokesperson did not return a request for comment.

9. JetBlue Airways: 62.08 percent

About 62 percent of JetBlue flights arrived on time in the first half of 2022.

JetBlue spokesperson Derek Dombrowski said 70 percent of the airline’s flights touch the northeast corridor, a congested air traffic region often plagued by severe weather events. The airline was also impacted by air traffic control constraints in April and by sick calls due to the pandemic, he said.

Multiple airlines have placed blame on staffing challenges at air traffic control centers manned by the FAA, which at times have led to delayed flights. The challenges have been especially pronounced in New York and Florida.

“JetBlue has taken a number of steps to improve our operation and reliability, and our completion factor has greatly improved in recent months,” Dombrowski said, noting that the airline now has record levels of staffing following a spring hiring and training push.

“These investments have brought a significant improvement despite continued constraints on the air traffic system in New York and Florida,” he added.

10. Allegiant Air: 61.63 percent

Allegiant Air clocked in at the bottom of DOT’s list, with 61 percent of flights arriving on time. Roughly 74 percent of Allegiant’s flights in the first half of 2021 arrived on time.

The airline said in a statement that some of its crews maxed out on the number of hours they could fly under FAA regulations during the first half of the year, and limited availability of back-up crews caused a number of delays. 

Allegiant, like other airlines, said it also grappled with crews being out of service due to COVID outbreaks and faces an “unprecedented” labor shortage.

“We are actively working to mitigate it by offering extra incentives to attract and retain employees, including higher wages, bonuses, work schedule flexibility and more,” the airline said.