Ryanair says it could have 40 routes operating from Belfast International Airport and four million passengers in the next two to three years.
Yesterday the airline revealed three new routes to Poland, including Gdansk, Wroclaw and Warsaw.
"They will be really strong for inbound tourism. Polish people coming here, yes, because you have a Polish community in Northern Ireland, and people wanting to come and visit Belfast," said Ryanair's chief marketing director Kenny Jacobs.
Speaking about the potential for the airline's Belfast base to grow four-fold, Mr Jacobs said the time frame "would be over the next two or three years".
He said the routes would be both winter and summer.
"Over the next coming three years would be the time frame we would say it's possible to get to around four million customers," he added.
"What it comes down to is three things.
"Have we a good deal with the airport, the second is have we enough aircraft and the third is it working, and do we see local demand?"
Belfast International boss Graham Keddie said passenger numbers could soon push the airport back into the top 10 in the UK.
Ryanair currently operates 11 routes from Belfast, with five daily flights to Gatwick.
Mr Jacobs said the growth for Ryanair in Belfast in just the last few months was "unprecedented" across the company.
Ryanair says bookings for the initial seven routes have been strong, while the new regular Gatwick route is also busy.