Aer Lingus and Stobart Air are to operate six new routes from Belfast City Airport.
They will fly to Edinburgh, Manchester, Birmingham, East Midlands, Leeds-Bradford and Exeter.
The new services will start on a phased basis from August.
Belfast City's chief executive Brian Ambrose said the airport is "delighted Aer Lingus is to establish a new base" at the airport.
The new routes will replace a significant part of the services lost when FlyBe collapsed earlier this year.
The airport will be an Aer Lingus Regional base with the routes operated by Stobart Air.
Five ATR72-600 aircraft will be based at the airport. These are turbo-props which can carry a maximum of 78 passengers.
Mr Ambrose said it was a significant development in "an extremely challenging environment".
"As an island off an island, air connectivity with the rest of UK is critical to the enabling Northern Ireland economic recovery," he said.
Stobart Air is promising "a high frequency schedule with convenient flight times".