Frontier is the worst US airline in 2023, and Spirit isn't far behind, according to recent study — see the list of the top 10 airlines

• Frontier was named the worst US airline in 2023 by claims management company AirAdvisor. 
• Spirit, another low-cost airline, was ranked the second-worst on the list. 
• Delta took the top spot as the best US airline this year.

AirAdvisor, a Boston, Massachusetts-based claims-management company, published its first-ever top 10 US airlines rankings on July 20. The company analyzed data from January 2022 until May this year.

AirAdvisor evaluated airlines on a ten-point scale based on nine criteria: reliability, comfort, safety, price, customer reputation, airline lounges, professional reviews, family travel, and traveling with pets. The overall score is taken from the average of the individual criteria scores.