Spain declared a state of alert Saturday over a wildcat strike by air traffic controllers, opening the way to criminal charges against strikers, the interior minister said.
It was the first state of alert in Spain since the death of General Francisco Franco in 1975.
The government declared the alert for 15 days in line with the constitution because almost all airports were paralysed by the action, said Interior Minister Alfredo Perez Rubalcaba.
This means "controllers can be mobilised and in case they do not turn up for work they will be committing a crime of disobedience stipulated in the military penal code," said Rubalcaba, who is also deputy premier.
Air France, KLM, Thai Airways and other major airlines cancelled all flights Saturday from Madrid-Barajas airport, as panel at the airport announced.
Other airlines listed as cancelling flights were Spanair, Ryanair, Easyjet and Aegean.
Flag carrier Iberia has already announced the cancellation of all flights nationwide until Sunday at 6am (0500 GMT).