Spain's government has agreed to sell a 49% stake in the state-owned airport operator, AENA.
"Today we approved launching the operation," the minister for public works, Ana Pastor, told a news conference after a ministerial meeting.
A total 28% of AENA would be floated in an initial public offer and another 21% placed directly with investors, the minister said.
Pastor stressed that AENA would remain a state-owned organisation, with the government holding 51%.
Spain, which lived through a construction boom that collapsed in 2008, has 49 commercial airports for international flights, the most of any country in Europe.