Ryanair is to open three new routes from Belfast's City Airport from November which is expected to create 270 new jobs.
The airline said today it was planning daily services to East Midlands, Glasgow and Liverpool from November.
Ryanair head of communications Peter Sherrard said: "We hope that this will be a strong driving force in Northern Ireland tourism which is very much having a honeymoon period with lots of new interest coming from Europe and the rest of the UK."
Currently the Dublin-based company's only Northern Ireland destination is the City of Derry in the north west.
Today's announcement will provide competition with easyJet and Flybe on the free domestic routes.
Airport chief executive Brian Ambrose said it was good news "for the economy, good news for tourism and good news for our growing customer base.
Media reports today suggest that Aer Lingus is also going to operating daily services from Belfast International to London Heathrow this summer. A spokesman for the airline said Aer Lingus in talks with a number of UK airports but declined to comment on the media reports.