Brian Ambrose said talks with government had taken place to establish if Stormont could aid the airport.
Frankfurt, Munich and Brussels are among his targets for new services.
He told BBC Radio Ulster's Inside Business programme: "Whether we get them across the line in one year or five remains to be seen."
Vueling, an airline new to Northern Ireland, recently announced it would start flights between George Best Belfast City airport and Barcelona next year.
Belfast International has also unveiled ten new routes, including Iceland.
A report on air connectivity is due to be published by Stormont in the coming months, and a new air development fund, similar to one that ran a decade ago, is being explored.
"We are working with government on funding these new routes," Mr Ambrose said.
"If we can find a state-aid compliant way of supporting route development, then the Department of Enterprise, Trade and Investment are up for that challenge."
In 2003, a Â£4m fund helped attract new routes such as New York.
Inside Business is on BBC Radio Ulster at 13:30 GMT on Sunday.
The chief executive of Belfast City Airport has said there is record interest amongst airlines for new, direct flights to Northern Ireland.