The 2018 Airline Quality Rating (AQR) report gave higher marks to nine of the 12 top US airlines in 2017, and the industry had the best combined score in the 27-year history of the annual report compiled by Embry-Riddle Aeronautical University.

Scores for American, ExpressJet, Frontier, Hawaiian, JetBlue, SkyWest, Southwest, Spirit and United airlines improved from 2016 to 2017, while performance worsened at Alaska, Delta and Virgin America.

Virgin America, which was acquired by Alaska Airlines, had the biggest year-over-year performance drop-off. However, Alaska Airlines was the top-ranked airline by AQR score, which is calculated based on factors such as on-time arrivals, involuntary denied boardings, mishandled baggage and a combination of 12 customer complaint categories.

Trailing Alaska in the AQR rankings were Delta, JetBlue, Hawaiian, and Southwest. Despite their improved AQR scores in 2017, low-cost Spirit and Frontier continued to sit at the bottom of the rankings.

Industry-wide, on-time performance declined from 81.4 per cent in 2016 to 80.2 per cent in 2017. However, airlines had fewer customer complaints and involuntary denials of boarding, and also had fewer reported incidents of mishandled baggage.