The European Union and the United States today delayed World Trade Organisation (WTO) investigations into how their main aircraft makers are financed.
Blocking the creation of panels at the first request is standard practice in WTO disputes, and the move by both powers had been widely predicted.
The blocking was announced after a meeting of the WTO's Dispute Settlement Body (DSB), called to consider complaints from both sides that the other provides illegal subsidies.
There was no indication when the DSB will meet again on the issue, involving the EU's flagship super-carrier Airbus and the US Boeing, but it could be within a few days.
Both trading powers had put requests for panels on their separate complaints on the agenda for the DSB meeting, but both refused to agree to the other's request, as they are allowed to do under WTO rules.
But if either bring a request again, it has to go ahead and a panel - or two panels - have to be formed.
Washington accuses Brussels of breaking trade rules with its help for Airbus, particularly with so-called launch aid. The EU claims Boeing has benefited from banned state assistance running to billions of dollars over the years.
Airbus, owned by Franco-German-Spanish firm EADS, overtook Boeing as the world's largest commercial aircraft maker in 2003.