Airline Reviews 2025: The least (and most) reliable airlines

For many people, flying can be one of the most stressful parts of planning a vacation, a business trip, or heading home to see family. Airline delays, flight cancellations, and missed connections turn air travel into a headache.

As the travel industry heads into a busy fall and winter period, travellers are keen to make the most of their trips without unnecessary disruptions. But while some airlines consistently stick to schedules and offer smooth experiences, others struggle, leaving travellers frustrated and uncertain.

With that in mind, the travel insurance experts at Compare the Market wanted to see which airlines were the most (and the least) reliable in both the UK and the US by looking at 38 of the busiest airlines flying out of UK airports and 14 major US carriers and assessing them on a range of factors.

From on-time flight performance and cancelled flights to mishandled baggage, passenger complaints and resolutions, and more, we were able to see which airlines are pulling their weight, and which are being left in the dust – here’s what we discovered!

And, if you’re looking for the 2023 iteration of this data, you can view it here.

Which is the most unreliable airline in the UK?

In the UK, Air India unfortunately leads the ranking for unreliability, with a total score of 71.68 out of 100. With a shockingly poor on-time rate of 35.3%, a negative customer sentiment score of 35%, and 112 complaints per 1,000,000 passengers, it’s safe to say that, for passengers seeking consistency, Air India is one to avoid.

And to show just how unreliable Air India is, the second most unreliable airline is Blue Islands, with a score of 51.03 – almost 20 points lower than Air India! Being located in such a remote region, it’s no surprise that Blue Island experiences long weather delays, with the average delay length being 41 minutes. Add to this a cancellation rate of 6.9% and you’re best avoiding these flights.

Next, Finnair takes third place, with a total of 47.67 unreliability points. Much like Blue Islands, those using Finnair are no strangers to cancelled flights, with the local Finnish weather resulting in 10.9% of flights never taking off. Though with a 50% customer uphold rate (complaints that were resolved in the consumers’ favour) and lower rankings for our remaining factors, Finnair manages to keep itself out of the top spots.

As for the other unreliable airlines in our top 5, budget carrier Jet2 sits in fourth place, scoring 45.03 thanks to a very low consumer uphold rate of just 18% and an overall negative sentiment of 35%, before we’re rounded out by TAP Air Portugal, who scored 43.75 by virtue of a 0% consumer uphold rate and average delay length of 19 minutes.

Which are the most unreliable US airlines?

Heading across the Atlantic, it seems that Frontier Airlines tops our US ranking for unreliability, with a total score of 79.92. In fact, Frontier Airlines had the lowest percentage of on-time flights (72.50%), a tied-lowest passenger rating (2), and the highest negative sentiment amongst passengers (45%), proving that the budget option isn’t always the best.

Then, in second, we have American Airlines with their score of 77.18. Similarly to Frontier Airlines, American Airlines has the third-lowest on-time flight score at 74.26% and the third-highest number of cancelled flights (1.43%). Add to this the highest number of mishandled bags per 100 cases (0.60), and it’s a wonder this well-known brand didn’t come first.

Moving into third, we have Envoy Air, a regional subsidiary flight service, and one that follows the trend of having low on-time flight levels – sitting at 76.34% – not to mention the most cancelled flights overall at 2.47%. However, in spite of this, Envoy Air still retains a surprising passenger rating of 5 stars, hence why it only placed third in our list.

Finally, to wrap up our top five, we have PSA Airlines, who claimed fourth place with a total score of 53.40 (again having low on-time flight levels at 72.62%), and in fifth, we have Spirit Airlines with their score of 47.48 – this is despite boasting one of the best on-time rates of 82.50%. For whatever reason, passengers don’t rate Spirit Air very highly, giving it just 2 stars.

Who are the UK’s most reliable airlines?

While there are clearly plenty of carriers out there who need to improve their service, it’s also true that certain airlines can provide a seamless travel experience, especially if you’re willing to pay a little extra on your flight.

Case in point, Austrian Airlines comes out as being the most reliable airline for the UK, scoring just 12.64 for unreliability and providing a stunning 100% consumer uphold rate. Add to this just 2 complaints per million passengers, and a very low flight cancellation rate of 0.6%, and it’s clear that Austrian Airlines knows exactly what they’re doing when it comes to passenger care.

Next, we have Singapore Airlines, whose score of 16.30 proves that they absolutely deserve their global prestige. With a passenger rating of 6.9 stars, a negative sentiment of only 5%, and a track record of never cancelling a flight, Singapore Airlines is definitely an airline worth flying with.

And finally, in third, we have JetBlue, with their score of 18.47. A renowned US flight brand, JetBlue enjoys an on-time flight rating of 88.4% (the 2^nd best) and a customer uphold rate of 100%, proving that they know a thing or two when it comes to customer service.

The most reliable US airlines

When it comes to reliable airlines in the US, it appears to be a similar story to the UK. Here, JetBlue are top of the charts as well, scoring a total of 9.94 for their high passenger rating (5.9), minimal negative sentiment (8%), low rate of mishandled bags (0.24), and a flight cancellation rate of just 0.21% – again proving that this airline is one to book with no matter where you’re flying.

Following on from JetBlue, we then have Allegiant Air, whose cancellation rate of just 0.09% helps to explain why they scored a total of 15.05 overall. Add to this the lowest rate of mishandled bags (0.09 per 100 cases), and a low negative sentiment score of 6%, and Allegiant Air certainly stand out as a stellar airline company.

Lastly, we have Republic Airways and their score of 25.92. Much like JetBlue and Allegiant, Republic Airways performs well across the board, including having the highest rate of on-time flights on our list (83.08%). Indeed, the only area really letting Republic Airways down is its cancelled flights, which average out at 0.83%, though this is still a very small number.

The worst US airlines for mishandled baggage

Few frustrations are as disruptive on holiday as lost luggage. Not only is it massively inconvenient, but it can also cause travel delays and be costly if you need to replace it. So, if you want to avoid baggage troubles the next time you travel state-side, passengers should avoid flying with American Airlines (0.60), Envoy Air (0.58), and United Airlines (0.53), all of which scored poorly when it came to baggage troubles.

The US airlines with the longest delays

Similarly to baggage problems, airline delays are another major frustration for travellers, disrupting connections and travel plans, especially for those on shorter trips or those travelling for an event or business.

Among US carriers, Envoy Air reported the longest average delay at 0.58 hours (34.8 minutes), while American Airlines wasn’t far behind, with average delays of 0.53 hours (31.8 minutes). PSA Airlines came next (0.39 hours, or 23.4 minutes), while Frontier Airlines averaged delays of 21.6 minutes.

At the other end of the spectrum, Allegiant Air impressed with the fewest delays (just 5.4 minutes on average), showing it is possible to deliver punctual travel consistently.