Singapore Airlines was the best airline in the world in 2022, according to the study.
US carriers fared poorly in the study with none cracking the Top 20.
Indonesia's Lion Air finished in last place in the study as the world's worst airline.
After years of battling it out for the title of Worst Airline in America, Spirit and Allegiant now find themselves near the top of an even more dishonorable list: Worst Airline in the World.
Allegiant and Spirit ranked among the worst airlines in the world behind only one other international carrier, Indonesia's Lion Air, according to a new study.
The study, by the Bounce luggage-storage app, used data from Official Airline Guide (OAG), Skytrax, FlightsFrom, the US Office of Aviation Consumer Protection, and individual airlines…
…to compare on-time arrival rates, cancellation records, customer ratings, seat comfort, in-flight meals and entertainment, staff service, and luggage allowances.
Spirit and Allegiant have topped worst-airline lists before. Travelers named Spirit the worst airline in the US in a 2022 American Customer Satisfaction Index survey.
Allegiant had the lowest percentage of on-time arrivals among US airlines through most of 2022, according to the Air Travel Consumer Report.
The new 2022 Bounce study - published online - broke carriers into separate US domestic and international best and worst lists. The US airline list added one component: Customer complaints from the US Office of Aviation Consumer Protection.
The study's authors created an apples-to-apples worldwide best and worst list at Insider's request.
Spirit finished tied for 59th place and Allegiant finished 61st out of the 62 largest airlines in the world based on departures, according to the study.
Allegiant's ultra-low-cost business model is very different from most other airlines in the study, according to company officials.
"Our fares are 'unbundled,' meaning that the base fare does not include the cost of amenities such as checked baggage, in-flight entertainment, priority boarding, or seat selection," an Allegiant official told Insider via email.
Allegiant's no-frills approach results in lower operating costs and customer savings, according to company officials.
"Most of our flights are under four hours, which doesn't allow enough time for meal service that may be offered on longer international or domestic flights," Allegiant said.
Allegiant doesn't offer in-flight entertainment. "The equipment adds weight to the aircraft, which burns more fuel," Allegiant said. "That increases the cost of operating the flight."
Indonesia's Wings Air tied Spirit for third worst airline in the world, according to the study.
Indonesia's Lion Air finished in last place, according to the study. Wings Air is a member of the Lion Air Group.
US-based carriers fared poorly in the 2022 study - with none breaking into the Top 20 ranking of best airlines in the world. Southwest (21st) was the top US airline, followed by Hawaiian (23rd), Delta (30th), and Alaska (31st).
The remaining major US carriers finished in the bottom half of the 2022 study: American (43rd), JetBlue (46th), Frontier (51st), and United (53rd).
Delta was the best domestic airline in 2021, according to the study.
International carriers dominated the top of the list for best airlines in the world. Singapore Airlines was the best airline in the world in 2022, according to the study.
Korean Air finished second ahead of All Nippon Airways, which came in third.
ANA was the best international airline in 2021, according to the study.
Notable international carriers near the bottom of the 2022 best/worst list: EasyJet (33rd), Air France (35th), Air Canada (41st), and RyanAir (49th).
Spirit officials did not respond to a request for comment.