Cornwall County Council is in a race against time to raise £21m to upgrade Newquay Airport when the RAF pulls out of St Mawgan next year.
A £5 departure tax started last year to help stem £1m a year losses
When the RAF goes, the civilian airport, which uses the same site, must provide air traffic control, radar and firefighters to keep its licence.
The council, which owns the airfield, is speaking to government departments and other agencies to raise the money.
Newquay, which has 360,000 passengers a year, is seen as vital to prosperity.
The Search and Rescue crews at St Mawgan had been due to pull out in April next year, but that has been delayed until October to give the council more time to ensure the airport meets Civil Aviation Authority standards.
Now the council is hoping government departments will help fill the financial black hole.
Steven Bohane, of the South West Regional Development Agency, said: "We have written it into our business plans as an absolutely essential priority for Cornwall."
The county council, which introduced a £5 departure tax last year to help stem losses of £1m a year, is also hoping passenger numbers will continue to rise.
Spokesman Colin Jarvis, said: "We have got some new airlines starting this summer.
"As soon as you get over the 500,000 a year mark, the viability becomes a lot stronger."
But Mark Pilling, editor of Airline Business Magazine, said low-cost carriers made it "almost impossible" to make profitable deals on services.
"They know the economic benefits that an air service brings and there is a lot of competition," said Mr Pilling.
"An airport like Newquay, in a region which is out on the periphery of the country, does not have the leverage that other airports have."