Ryanair filed a complaint against NATS, UK's main air traffic control provider, the carrier announced on September 3, 2018. The low cost carrier claims that London Stansted Airport (STS), its main British base, is discriminated against by ATC. According to the data provided by the airline, half of the delay due to ATC is suffered by Stansted. NATS denies the accusation.

The complaint relies on data provided by the British Civil Aviation Authority (CAA) showing that during the first quarter of 2018, 52% of delays caused by ATC were suffered by Stansted, far more than Luton 30%, Gatwick 10%, City 8% and Heathrow 0%. According to Ryanair, this year will be the worst in terms of ATC disruptions at Stansted.

The Irish airline sees a conflict of interest here: British Airways and Easyjet, based respectively in Heathrow and Gatwick, are both shareholders of NATS.

“NATS does not discriminate between airlines or airports,” NATS told AeroTime via mail. “Ryanair performance this summer cannot be blamed on UK air traffic control. The figures Ryanair quote from the beginning of the year coincide with the introduction of new technology that affected the number of flights in and out of Stansted during that period. Luton airport was similarly affected at that time and other airports were affected at other times over a seven month period. All airlines and airports were notified of the timetable in advance and understood the new technology will help us increase capacity safely in the future.”

A year ago, in August 2017, Ryanair issued a similar complaint against NATS to the CAA. The investigation of the government body concluded that while there were no sign of discrimination, the ATC provider would be under increased scrutiny, as it failed to answer to shortage in staff.

Ryanair is regularly in conflict with European air traffic controllers. In 2016, the company launched the Airlines for Europe initiative, asking the European authorities to take actions preventing ATC strikes to affect consumers and businesses.

British airlines IAG and easyJet, Irish Ryanair and Hungarian Wizz Air announced on July 24, 2018, that they filed a complaint against France to the European Union on the grounds that air traffic controllers' strikes limit the freedom of movement.