Ryanair Holdings Plc could cease flights within Britain once the country leaves the European Union, rather than take steps to comply with new regulations.

As an Irish company, Europe’s biggest discount carrier could require a U.K. air operating certificate, or AOC, in order to continue domestic services there once Brexit is implemented, Chief Financial Officer Neil Sorahan said Wednesday.

Since only 2 percent of Ryanair’s network involves intra-U.K. operations, it may decide to withdraw the flights, Sorahan said at the 2017 Global Airfinance conference in Dublin. Routes affected would include Edinburgh and Glasgow to London Stansted, Belfast-London Gatwick, and three from Londonderry.

Ryanair was one of the most outspoken opponents of Brexit in the run-up to last June’s referendum. Afterward, the company said it planned to slow U.K. expansion, though Ryanair last week announced nine new routes from Stansted and the deployment of extra aircraft.

EasyJet License

EasyJet Plc, Europe’s No. 2 low-cost carrier, faces a potentially tougher challenge since it may require a European license to carry on operating the bulk of its current timetable. The airline has said that it’s actively exploring how best to approach the problem and could even buy another company to acquire an AOC, or move its registered headquarters to an EU state.

Just three staff, handling ground, flight and engineering operations, are needed in a location to qualify for an AOC, and the process can take only a few months.

London-based IAG SA, the owner of British Airways, already has licenses in Spain and Ireland. The need for foreign AOC’s would be rendered redundant should Britain be able to agree terms allowing it to remain part of the single European aviation market even after leaving the EU.

To contact the reporter on this story: Benjamin Katz in London at [email protected] To contact the editors responsible for this story: Chris Reiter at [email protected], Christopher Jasper

©2017 Bloomberg L.P.

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Photo Credit: Ryanair Boeing 737s wait in Edinburgh. If the company does not obtain a UK operating certificate, it will not be able to fly domestic routes from Edinburgh. David Moir / Reuters