Ryanair took aim at the CAA for enabling NATS to increase air traffic control fees airlines have to pay.
ATC service fees will rise by a quarter through 2027.
The hike comes months after a major IT system meltdown at NATS led to over 2,000 UK flights being cancelled.
Thousands more were delayed during the August bank holiday period.
“NATS should not be rewarded for these repeated failures with a 26% price increase,” the airline said.
Since the debacle Ryanair has been one of NATS’ loudest critics, calling for the head of the service to resign.
Ryanair says it already pays NATS almost €100m per year for air traffic control services.
“NATS should be obliged by the CAA to reimburse airlines the costs.”
The airline says it cost it £15m due to ATC failures.
“Until NATS provide full ATC staffing at weekends during the busy summer season no price increases should be awarded,” it said.
“Ryanair believes there will be no improvement in NATS rosters, efficiency or services, until CEO Martin Rolfe is sacked.”
“The CAA should not be rewarding NATS for its incompetence.”
Ryanair’s CEO Michael O’Leary added: “We are astonished at the CAA’s decision. NATS continues to call for last-minute schedule cuts at Gatwick due to mismanaged rosters in the ATC tower.”
