Flying can be a pretty stressful affair. Airport security lines are unpredictable, planes are very loud, and to top it all off there’s always the chance that you’ll end up waiting hours at a grey, miserable terminal if your flight is delayed. Although you might not be able to control those first two stresses, your chances of being on time vary dramatically depending on which airline you go for.
The UK Civil Aviation Authority (CAA) keeps track of all things going on in the sky, including how punctual airlines are. AirAdvisor has sifted through the latest CAA data, from January to September 2025, to reveal the most unreliable carriers in Britain.
AirAdvisor revealed that TUI has been the UK’s least on-time airline, with only 57 percent of its flights taking off and arriving as intended. The CAA considers a flight ‘on-time’ if it takes off or lands within 15 minutes of the time on your boarding pass.
AirAdvisor explained that TUI’s punctuality had actually increased from previous years, when some months saw less than half of the airline’s flights arrive on time. Despite that, it remains the least reliable provider in the UK.
A spokesperson for the consumer advice website noted that, ‘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’.
Blue Islands, which primarily operated flights between the Channel Islands and mainland UK, was the nation’s second least reliable airline. Unfortunately, it ceased trading and cancelled all future flights with immediate effect on November 15, so none of its flights will ever be on time, or late, ever again.
The least punctual airlines in the UK in 2025
Here are the five worst airlines for delays in Britain for 2025 according to AirAdvisor.
- TUI
- Blue Islands
- Swiss Airlines
- KLM
- Jet2
After 90 years, this historic British airport will shut in 2026.
Plus: The spectacular British islands that are one of the top places to travel in the world in 2026
Stay in the loop: sign up to our free Time Out UK newsletter for the latest UK news and the best stuff happening across the country.