“We are serious in our dealings with investors, we always are,” the union’s North German district manager, Daniel Friedrich, told dpa.  “But of course we also expect Airbus to seriously examine the other alternative and not just threaten us with further job cuts.”

Friedrich said it was “indisputable” that the single-part production had to be made “fit for the future – the dispute is how do we do it and with whom.”

“The investor solution is not our solution, but it is our job to deal with it seriously.”

Airbus has not commented on Friedrich’s remarks, but had previously pledged billions in investments and “comprehensive guarantees” on sites and employment conditions at the locations, which extend until 2025. However, the union is demanding a commitment beyond 2030, when production of a successor to the successful A380 family is due.

“The question then is how much of the next generation of aircraft will still be made in Europe,” Friedrich said.