Britain's most complained-about airline isn't Ryanair or easyJet.

Whilst air travel, at its finest, resembles a contemporary marvel - whisking us across continents in mere hours in ways our ancestors couldn't have imagined - it can equally prove intensely irritating and exasperating.

From rising at ungodly hours for early departures, to queuing endlessly for flights scheduled to depart ages ago, splashing out eye-watering sums at airports, or enduring cramped-seat discomfort, there's no shortage of grievances.

And complain we certainly do.

Latest data from the UK's Civil Aviation Authority reveal that over 43,000 complaints were lodged regarding airlines operating in Britain between mid-2024 and March 2025. Whilst the catalogue of potential grumbles is limitless, the most frequent involve disruptions, denied boarding, lost or damaged baggage, and lack of assistance for disabled passengers.

Have you had a complaint-worthy flight? Email webtravel@reachplc.com

This comes after a stretch of particularly turbulent months for the aviation industry. The opening five months of 2025 saw tens of thousands of delays and cancellations, EuroNews reports.

Dutch operator KLM axed the highest number of flights during this timeframe, with 2,760 cancelled, trailed by British Airways (1,763) and Germany's Lufthansa (1,757), according to FlightRight. Finnair recorded the highest cancellation rate during those five months, grounding 3.35% of its flights from a total exceeding 43,000 journeys.

Regardless of the nature of a passenger's grievance, provided a flight departed from or arrived in the UK, they're entitled to lodge a complaint with the UK Civil Aviation Authority.

Examination of the Authority's most recent figures reveals that Wizz Air topped the table for complaints per million passengers carried, relegating Ryanair to second place. The Hungarian carrier won this unwanted accolade by a considerable margin.

Between mid-2024 and March 2025, it received 10,548 customer complaints, equating to 918 grievances per million passengers. Put simply, for every traveller who flew, nearly 1,000 lodged a complaint during this timeframe.

Working in Wizz Air's favour is its comparatively modest 'complaint upheld' rate of 47% during this period. The airline paid out £1,482,183 in compensation, averaging £651 per customer.

By comparison, British Airways recorded a significantly lower complaint rate (192 per million customers), yet 83% were upheld. BA distributed £6,238,378 in total compensation, averaging £837 per customer.

(UK operating airline: complaints per million customers; complaints upheld; average award)

"At Wizz Air, every minute matters and customers are at the heart of everything we do. Since 2024, we have made significant investments across every part of our operations, including our Customer First Compass initiative - a £12 billion framework launched in 2025 to ensure we deliver the best possible service for our customers. This investment is already delivering results. In 2025, our UK flight completion rate was 99.8% - one of the best in the entire industry, while our on-time performance also improved by 14.23% compared to 2024. As a result, in 2025 customer satisfaction ratio already increased by 7% point year-on-year.

"We recognise that disruption does occasionally occur, on many occasions due to factors outside of our control. We are focused on responding quickly and effectively when it does. Our automated Chatbot, Amelia AI, is available 24/7 to address most customers' enquiries and needs. Our customer service agents are also available by phone, and customers who wish to submit a formal claim can do so easily via the Wizz Air website. The MyJourney feature in the Wizz Air app also provides passengers with real-time updates so they can stay informed and confident about their travel plans.

"The progress we have made reflects the sustained effort and investment dedicated to improving our service, which remains a daily focus. However, we recognise there is more to be done. We remain fully committed to strengthening our operations, reducing delays and cancellations, and ensuring fast, reliable support for our customers whenever disruption occurs."