Ryanair is urging passengers who suffer UK air traffic control (ATC) delays to email British Transport Secretary Heidi Alexander to complain.
The airline has included the Cabinet minister's personal parliament email address on a website named Air Traffic Control Ruined Your Flight. Her email address was already publicly available.
Some 5,782 Ryanair flights were affected by delays caused by the UK's ATC provider Nats between the start of the year and September 1, the carrier said.
Ryanair called on Ms Alexander to "fix" Nats, which it described as "mismanaged and short-staffed".
The UK government has the largest shareholding in the public-private company at 49%. It also holds a golden share, giving it additional control.
Ryanair's director of communications Jade Kirwan said: "It is unacceptable that Nats' ATC mismanagement and staff shortages continue to cause disruption to UK flights and passengers".
"Already this year, more than one million Ryanair passengers - many of whom were travelling on holidays with young families - have suffered unnecessary and avoidable ATC delays, and all because Minister Alexander has not taken action to properly staff UK ATC services," Ms Kirwan said.
"Ryanair calls on all passengers to visit the Air Traffic Control Ruined Your Flight webpage and demand that their national transport minister - like Minister Alexander - take urgent action to fix their national ATC services and stop these needless ATC delays," she added.
The website features a mocked-up video of European Commission president Ursula von der Leyen slapping an airline passenger in the face.
Ryanair has accused Ms von der Leyen of failing to take sufficient action to improve ATC services.
