Air services in Spain are returning to normal after an unofficial strike by air traffic controllers disrupted hundreds of thousands of journeys.
But thousands of passengers are being warned to expect further delays as Spain works to clear a huge backlog.
Officials said 250,000 people were hit by Saturday's walkout, amid a long-running dispute about working hours.
Spain's government imposed emergency measures not seen since military rule in an attempt to halt the strike.
The state of alert allows the government to arrest those who refuse to work, Spain's interior minister said.
Threats of further strikes over the Christmas and New Year period would be quashed by the government, the AFP news agency quoted Alfredo Perez Rubalcaba as saying.
Air traffic controllers are now working under military supervision, with army trucks seen at many of Spain's major airports. BBC News
