The fate of a controversial insurance scheme to cover Europe's airlines against third party war and terrorism risks will be decided at a crunch meeting in Brussels on 17 June.
Months of work by the UK's top brokers and intensive lobbying by airline chiefs could come to nothing unless all 15 EU member states back the Eurotime scheme.
The UK government has been among the most sceptical to the scheme and has consistently argued against intervention in the aviation insurance market.
It stepped in to offer state aid only when a withdrawal of cover by commercial insurers in the wake of the 11 September attacks threatened to ground UK aircraft.
John Cruse, executive director of aviation at Aon, has played a leading role in putting together the Eurotime scheme.
He said airlines and brokers needed to know if governments had the will power to make it work.
The scheme was presented to the presidents of European airlines in April and the EU's insurance group in May.
"We need the airline presidents to lobby their governments and to say this is the way forward," Cruse said.
If it fails, airlines could be forced to buy the limited insurance available on the commercial market.
Policies typically allow insurers to cancel cover at seven days' notice prompting airlines to complain that they cannot work under such uncertain conditions.