As a result of the attack, which also injured 19 people, the Spanish government has declared an end to a nine-month ceasefire which many had hoped would lead to peace.
Eta had declared a ceasefire in March after 40 years of armed struggle for independence of the Basque Country in which it killed more than 800 people.
The bomb went off on December 30, 2005, in a multi-storey car park at Madrid international airport.
Palate was believed to have been sleeping in a car that was destroyed in the bombing.
A second Ecuadorian man who was at the airport separately, and who is also thought to have been sleeping in a parked car, is still missing.
His body is also suspected to be buried under an estimated 40,000 tonnes of concrete debris.
Batasuna, a political party affiliated to Eta and banned for its links to the organisation, insists it still wants to negotiate peace and Basque politicians maintain there is no proof that Eta was behind the bombing.
On Wednesday Batasuna said it was caught by surprise by the car bomb.
"I don't think anyone expected an attack like the one in Madrid," Joseba Alvarez, a leading member of Batasuna, told Basque radio in a remark which some might interpret as signalling divisions within the region's independence movement.
Jose Luis Rodriguez Zapatero, the Spanish prime minister, is due to visit the scene of the explosion on Thursday morning and is expected to meet the families of the victims.
On Saturday he said: "I have decided to suspend all initiatives for dialogue with Eta."
But Candido Conde-Pumpido, Spain's attorney-general, was quoted by Spanish newspaper El Mundo as saying that the airport attack was not part of a renewed campaign by the Basque separatist organisation.
"I think that Eta's time of terrorism has run out forever and the situation is irreversible. I think Eta has been defeated and we are at its funeral," he said.