As the busy holiday travel season approaches, a new analysis has revealed which US airlines are most likely to test travellers’ patience. Frontier Airlines has been named the most unreliable carrier in the United States for 2025, according to fresh research from Compare the Market.
The study, conducted by the comparison site’s travel insurance division, assessed major American airlines across key performance metrics, including on-time arrivals, flight cancellations, baggage handling, and passenger sentiment. The findings come as millions of US holidaymakers prepare to take to the skies, with reliability topping the list of traveller concerns.
Frontier Tops the List
Frontier Airlines emerged as the nation’s least reliable operator, scoring 79.92 out of 100 on the index. Despite maintaining a relatively modest cancellation rate of 1.2 per cent, the Denver-based budget carrier performed poorly on customer sentiment, recording a striking 45 per cent negative rate on social media — the highest of any airline assessed. Passenger satisfaction was similarly low, with Frontier earning just two out of five stars in traveller reviews.
American Airlines, the country’s largest carrier by fleet size and passenger volume, ranked second-worst overall. The airline achieved an on-time performance of 74.26 per cent but was hampered by a large volume of unresolved customer complaints and a 32 per cent negative sentiment rate among passengers.
Regional airlines also featured prominently among the least reliable. Envoy Air, a subsidiary of American Airlines Group, placed third with an on-time record of 76.34 per cent and the highest cancellation rate in the top five at 2.47 per cent. PSA Airlines, another American regional affiliate, followed in fourth with an on-time rate of 72.62 per cent and 2.14 per cent of flights cancelled.
Rounding out the list, ultra-low-cost carrier Spirit Airlines took fifth position. Although it posted a comparatively strong on-time performance of 82.5 per cent, Spirit’s reputation suffered from passenger dissatisfaction, marked by a 28 per cent negative sentiment rate and a two-out-of-five customer rating.
The Full Ranking
According to Compare the Market’s analysis, the five least reliable US airlines in 2025 are as follows:
| Rank | Airline | On-Time Flights | Cancelled Flights | Negative Sentiment | Passenger Rating | Total Score |
|---|---|---|---|---|---|---|
| 1 | Frontier Airlines | 72.51% | 1.2% | 45% | 2 | 79.92 |
| 2 | American Airlines | 74.26% | 1.43% | 32% | 2.8 | 77.18 |
| 3 | Envoy Air | 76.34% | 2.47% | 15% | 5 | 61.20 |
| 4 | PSA Airlines | 72.62% | 2.14% | 6% | 5 | 53.40 |
| 5 | Spirit Airlines | 82.5% | 0.44% | 28% | 2 | 47.48 |
Customer Experience Drives Rankings
The study found that public perception and passenger experience played a major role in determining overall reliability scores. Despite only moderate differences in punctuality or cancellation rates among carriers, airlines with weaker customer service reputations fared significantly worse.
Frontier’s particularly low sentiment and satisfaction scores highlight ongoing concerns about service standards in the ultra-low-cost segment, where operational efficiency often takes precedence over passenger comfort. American Airlines’ second-place ranking underscores the challenges facing legacy carriers in managing large customer bases and complex service operations.
In contrast, smaller regional airlines such as Envoy Air and PSA Airlines were penalised primarily for their higher cancellation rates, reflecting operational limitations within regional networks that are more vulnerable to weather disruptions and scheduling inefficiencies.
Travel Insurance Advice
Adrian Taylor, Executive General Manager of General Insurance at Compare the Market, said the findings underscored the importance of reliability when planning travel, particularly during the peak holiday season.
“Going on holiday should be exciting, but the experience of flying plays a huge part in your trip. Delays, cancellations, and poor service can quickly turn a dream vacation into a stressful ordeal,” he said.
“With this in mind, reliability should be a top priority when choosing an airline. Unfortunately, some airlines consistently rank lower on factors such as on-time performance and customer satisfaction. Understanding which airlines struggle the most can help travelers make more informed decisions and avoid frustrating experiences.
“It’s also important to remember that flight disruptions can happen with any carrier. Travel insurance can be a vital safety net, helping you recover financially from unexpected issues like significant delays or lost luggage, ensuring peace of mind while you’re on the go.”
Industry Implications
The results come at a time when US carriers are under pressure to restore traveller confidence after several years of operational challenges, including pilot shortages, severe weather events, and high post-pandemic demand.
For UK travellers connecting through or flying within the United States, the rankings offer a timely reminder to factor reliability — not just price — into their airline choice. With Compare the Market’s data pointing to ongoing service disparities, passengers may find that budget fares come at a greater cost to convenience and peace of mind.
