Fórsa has demanded that Ryanair management consults with the union ahead of any decisions that could impact on the jobs, incomes or working conditions of its members. The warning came as the airline said it may close some bases between November and next summer because of the debacle over Boeing B737 MAX aircraft.

No specific bases or routes have been identified by the company, which said it was talking to airports about the issue. It also said it would consult with staff and unions.

Responding to media queries, a Fórsa spokesperson said the announcement would cause concern to Ryanair staff.

“At this point we have no specific information about any routes or bases that might be affected. Fórsa will be watching the situation closely, and will expect the airline’s management to consult with the union in advance of deciding or announcing any measures that could impact on the jobs, incomes or working conditions of union members,” they said.

Ryanair’s growth projections have also been hit by delays in deliveries of the Boeing 737 MAX planes, which were grounded by regulators after 346 people died in crashes in Ethiopia and Indonesia.