The EU and the US have both said they are ready to continue talks to break the deadlock on cutting state aid to aircraft makers Boeing and Airbus.
EU Trade Commissioner Peter Mandelson said both sides should "pause for further thought" and review the case.
The two economic powers were supposed to find a solution by Monday in order to prevent the issue going back to the World Trade Organisation (WTO).
Each side accuses the other of boosting the industry with illegal state aid.
"I regret that it has not been possible to reach an interim agreement by 11 April," Mr Mandelson said in a statement.
"But given the complexity of the issue, this is perhaps not surprising."
He added the EU was interested in reaching a temporary accord to reduce levels of government support in view of a more comprehensive agreement in the long term.
The dispute has intensified after Airbus started producing what will become the world's largest passenger plane, the A380 superjumbo.
'Hopeful'
The US accuses the EU of having funded the project with generous subsidies, while the EU claims that Boeing is receiving similar help in the US for its Dreamliner, a mid-sized plane.
But both sides agree that a long and costly WTO dispute should be avoided.
On 11 January, the US government and EU gave themselves 90 days to resolve their dispute over aircraft subsidies instead of suing each other through the WTO.
On Friday, Richard Mills, a spokesman for the US Trade Office, said the US regretted that no agreement had been reached yet, and remained ready to negotiate on the basis of the 11 January agreement.
The US would not proceed with litigation unless the EU made fresh subsidies to Airbus.
Guy Hicks, a spokesman for EADS North America, Airbus' parent company, said: "We continue to remain hopeful and optimistic that this will be resolved at the government-to-government level."
Boeing spokesman Amanda Landers said: "The goal of the 11 January agreement between the US and the EU is to end subsidies.
"Boeing stands firmly behind the US government's efforts to reach the goal, including WTO litigation if necessary."
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