Iberia pilots are due to take strike action this month over plans by parent company International Airlines Group to set up a Spanish budget carrier.
The walkouts have been called for December 18 and 29 with pilots claiming salaries at Iberia Express will be too low.
Iberia Express is due to be launched in April 2012 with Iberia deploying 40 aircraft to the lowcost start-up. But pilots fear job losses with Iberia hiring new staff at lower salaries.
A vote on industrial action will be held next week as pilots’ union, Sepla, said Iberia had rejected its compromise proposals.
Union president Justo Peral said: “Sepla has decided to adopt the last measure which we wanted to adopt: a strike.”
The new airline being established by Iberia and British Airways owner IAG is to run short and medium range flights from Madrid, where there has been increased competition from other low-cost carriers and high speed trains.
Unions representing other Iberia workers have decided not to take part in the strike.