Newquay Airport has received a major vote of confidence with an £8m grant from the South West Regional Development Agency (RDA).
Newquay Airport is set to top 400,000 passengers this year
The RDA said the airport was key to the economic regeneration of Cornwall.
The investment appears to secure its future after the Ministry of Defence (MoD) said it was withdrawing from RAF St Mawgan next year.
The airport operates from the RAF site, which is to be mothballed together with its essential services.
The RDA's investment in Newquay Airport is part of a £21m package being assembled by Cornwall County Council, with potential contributions also coming from the Department for Transport and Objective One which directs EU funding to deprived areas.
The council, which owns the airport terminal, is currently negotiating an £8m replacement for the air traffic control systems.
A new expanded terminal opened in March and the council aims to increase the number of passengers passing through the airport.
The figure is set to top 400,000 this year, but the council is aiming for one million to make the airport, which costs the council £1m a year, a profit-making business.
The council is negotiating with the MoD to buy the site when RAF operations cease in November next year.
RDA chairman Juliet Williams said: "Newquay Airport needs to operate successfully to bring people into the county for business and pleasure."
Andrew Mitchell, the county council's executive member for the economy, said the RDA grant would guarantee expansion of the terminal for the next four years.
"It's absolutely fantastic, an early Christmas present for the Cornish economy," he said.
"We are now looking forward with hope to our other applications and this is a very good start."
The RDA is also giving £12m to St Austell for the final phase of the town's massive redevelopment.