Ryanair boss Michael O’Leary has taken a fresh swipe at his apparent nemesis after a weekend of delays at one of the U.K.’s busiest airports, calling for the man he sees as responsible to step down and “allow someone competent” to take his place.

London Gatwick Airport was beset with air traffic control issues over the weekend owing to staff shortages at its contractor Nats. Some 57 flights were canceled from the airport, while another 240 were delayed on Sunday.

EasyJet was the biggest victim of cancellations, while other operators including British Airways and Wizz Air also faced heavy disruption.

O’Leary, whose airline operates flights to and from Gatwick, wasn’t sparing in his criticism of the air traffic control group over the recurring problem of staff shortages.

“This is the latest in a long line of cock-ups by U.K. Nats, which has yet again disrupted multiple flights and thousands of passengers at Gatwick. Airlines and passengers deserve better,” O’Leary said.

“Ryanair again calls on U.K. Nats chief executive Martin Rolfe to step down and allow someone competent to run an efficient U.K. ATC service, which airlines and passengers are entitled to expect.

“If he won’t go, then Louise Haigh should sack him,” O’Leary said of the new U.K. transport secretary.

A representative for Nats didn’t immediately respond to a request for comment.

O’Leary has been in a feud with Nats and its chief executive Rolfe since last year’s August bank holiday, when staff shortages forced Ryanair to cancel 370 flights at an estimated cost of $25 million.

Nats said in September last year that 30% of its staff were forced off work for “a variety of medical reasons including COVID.”

In April, Ryanair said it would be suing Nats for last summer’s travel chaos in a bid to recoup losses from cancellations and the ￡100 million a year it pays in ATC fees.

O’Leary’s feuds

While his rivalry with Rolfe has been brewing for months, O’Leary has made time to stoke his other feuds over the summer months.

After rival budget airline Wizz Air introduced a €499 all-you-can-fly pass in August, O’Leary dismissed the pilot project as “a bit of a marketing scam.”

His comments prompted Wizz Air’s chief corporate and ESG officer Yvonne Moynihan to label them “not only provocative” but also “inaccurate.”

O’Leary then found himself in the crosshairs of the outspoken Wetherspoons boss Sir Tim Martin after taking a pointed dig at the low-price U.K. pub chain.

The Ryanair chief executive called on the Labour government to introduce a two-drink limit at airports to curb a rapid increase in air rage on his flights.