The 12 worst airlines for UK flight delays, according to the latest Civil Aviation Authority (CAA) data

New analysis of Civil Aviation Authority (CAA) data covering January to September 2025 shows the worst airlines for UK flight delays.

Air passenger rights experts, AirAdvisor, assessed CAA Aviation Trends punctuality data which is published every three months, for the first three quarters of 2025.

This enabled the company to establish the average on-time performance of the United Kingdom’s most popular carriers, so far this year.

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The study analysed the performance of the 20 airlines with the most passengers embarked and disembarked at UK airports for each quarter, and tracked the proportion of their flights which were delayed, according to the CAA.

The CAA considers a flight as "on-time" if it arrives or departs from the airport gate within 15 minutes of its scheduled time.

Discussing the research, AirAdvisor CEO, Anton Radchenko explains: “Many factors contribute to an airline’s on-time performance, not all of them within an airline’s control, but past performance remains a key indicator of a carrier’s future ability to keep flights on schedule.

“British consumers should be relieved to hear that in the most part, flight delays and cancellations are falling and 2025 has been something of a turning point year for the aviation industry, with disruptions finally decreasing to close to pre-Covid levels.

“That said, millions of passengers each year find themselves in a position where their flights are delayed or cancelled.

“And in many cases, you may be due up to £520 in compensation for the inconvenience caused, thanks to UK government regulation UK261, depending on the cause of the disruption and the notice you were given by your airline.”

Here are the top 12 airlines said to be the worst for UK flight delays...