The worst airline for UK flight delays in the past two years has insisted passengers “should trust” it this summer.

Wizz Air’s UK managing director Marion Geoffroy said the Hungarian carrier has reviewed “every single aspect of its operations” to boost resilience, and has performed well in recent months.

It has overhauled flight schedules, rostering and the availability of spare aircraft parts since 2022.

In an interview with the PA news agency, Ms Geoffroy said: “Passengers should trust Wizz and they should book with Wizz.

“We don’t see any area except for air traffic control (ATC) where I would have concerns.

“Of course we might face some strike actions at certain airports but in terms of our operations – what we control – we’ve put a lot of strength in the entire system.”

Wizz Air operates flights from eight UK airports including Birmingham, Edinburgh, Gatwick and Luton.

Analysis of Civil Aviation Authority (CAA) data shows Wizz Air’s departures from the UK last year were delayed by more than 46 minutes on average, which was longer than any other airline.

The carrier was also ranked last for punctuality in 2021.

In December 2022, the CAA said it had “significant concerns” about Wizz Air as it was delaying paying refunds for cancelled flights, and its passengers were far more likely to make escalated complaints than those of other airlines.

The regulator also said the carrier faced a “large number” of county court judgments, which are orders to pay money owed.

Asked about the airline’s performance during the last two years, Ms Geoffroy said: “We do apologise. We don’t want this to happen again.”

She said that by operating flights as early and late in the day as possible, the airline has been able to introduce “extra buffers” involving aircraft being scheduled to remain on the ground for part of the afternoon, limiting the knock-on effect of morning delays.

More staff are working on two flights per shift rather than four, reducing the likelihood of disruption meaning labour laws prevent them from completing the final flight, forcing it to be cancelled.

Wizz Air has made more spare aircraft engines and other parts available this summer to cut the impact of faults.

Ms Geoffroy said the airline has also worked with airports and ground-handling companies to ensure there is no repeat of the staffing shortages that caused much of the chaos during last year’s surge in demand for air travel.

She said airline managers have “tested ourselves already” during peak periods this year over Easter, bank holiday weekends and half-term school holidays.

“It’s gone well,” she said. “We were mostly affected by external factors such as ATC strikes or weather. They were the main reasons for disruption so far.

“We know we’re going to face them in July and August because the ATC situation is not going to be solved this summer.

“But we’ve seen that these buffers we’ve put in place have helped us overcome disruption due to external factors.

“We’re very happy with April, May and June. The number of flights we cancelled was the lowest in the industry compared to our peers.”

Ms Geoffroy added that the airline has dealt with more than 80% of its outstanding CCJ cases and hopes they will all be closed by the end of the summer.

Rory Boland, editor of consumer magazine Which? Travel, said: “Wizz Air was named the worst short-haul airline in our recent survey, and its dismal record on cancellations, delays and meeting even basic standards of customer service mean it should be avoided at all costs.

“Passengers have been expected to sit back and put their trust in airlines like Wizz Air for far too long, only to be repaid with having their travel plans ruined and their rights disregarded.

“It’s time for Number 10 to finally show it is on the side of consumers and legislate to give the aviation regulator fining powers, so it has the teeth to take airlines to task.”

It emerged this week that Gatwick is suffering more flight delays due to ATC limits than any other major European airport.

EasyJet cancelled 1,700 summer flights – mostly from Gatwick – in response to “unprecedented” ATC restrictions.