Spain has placed striking air traffic controllers under military authority and threatened them with jail terms in an unprecedented emergency order to get planes back in the skies and clear chaotic airports clogged with irate travellers.
Hours after the order was issued at an emergency Cabinet meeting, officials said strikers were returning to work but that it could take up to two days before flights return to normal.
Spain got the all-clear from Eurocontrol, Europe's air traffic control agency, to reopen airspace which closed on Friday when the wildcat strike began, ruining the start of a long holiday weekend for hundreds of thousands of people.
Many travellers stood shoulder-to-shoulder at airport terminals or slept anywhere they could, including hunching over abandoned customer service desks or against luggage trolleys.
The chaos served up yet another headache for a beleaguered Socialist government writhing at the centre of Europe's debt crisis and struggling to overcome recession as it trails badly in the polls with elections due in 2012.
A few flights have resumed at more than half a dozen airports including Madrid, Bilbao and Las Palmas in the Canary Islands, the civil aviation authority Aena said.
But development minister Jose Blanco said it will be a while before planes can start taking off and landing at normal levels in one of Europe's top tourist destinations and a sea of stranded passengers can make new travel arrangements. "We think that in 24 to 48 hours we can be back to normal if the air traffic controllers comply with the order and all of them work in line with their obligations," Mr Blanco told Spanish television.
Eurocontrol and the controllers' union USCA also said things were gradually getting back to normal after the government's threat of jail for defiant strikers.
In announcing the approval of a "state of alarm" after the emergency Cabinet meeting, Deputy Prime Minister Alfredo Perez Rubalcaba accused air traffic controllers of "blackmailing all of our citizens". He apologised to angry passengers who spent Friday night sleeping at airports.
The air traffic controllers launched their stoppage in the culmination of a long-running dispute with the government over working conditions, work schedules and benefits.