All domestic regional points lost with the collapse of Flybe from Belfast City airport are being re-established by Aer Lingus Regional.
Emerald Airlines, operator of the Aer Lingus Regional network, is to take on former Flybe connections to East Midlands and Newcastle.
Flights to East Midlands start on March 26 with a daily frequency rising to double daily from mid-April.
A daily service between Belfast City and Newcastle will run from April 28.
Fares start at £34.99 one-way.
The airline aims to add more than 180,000 seats this summer from Belfast City, with more than 400 weekly flights to and from the airport.
The network expansion will see Aer Lingus Regional serve Birmingham, Cardiff, Edinburgh, Exeter, Glasgow, Leeds Bradford, Manchester and Southampton from Belfast plus new services to East Midlands and Newcastle in addition to summer flights to Jersey and Newquay.
Head of commercial Ciaran Smith said: “We are very pleased to be strengthening our schedule out of Belfast City airport. As the demand for travel options from Belfast only increases, these two new routes will no doubt be warmly welcomed.
“Earlier this week we announced that we will be adding 15,000-plus seats immediately across our existing network from Belfast City, and we will continue to grow these services in the months ahead.”
Belfast City commercial director Katy Best added: “Following the collapse of Flybe, East Midlands and Newcastle were the airline’s only destinations not served by other carriers from Belfast City airport.
“Having Emerald Airlines step-up and operate the Aer Lingus Regional services on both routes, in addition to its already extensive network from Belfast City, is therefore excellent news as it leaves no Flybe destination unserved.
“Maintaining a robust route network and ensuring connectivity to and from Northern Ireland remains our priority, and we look forward to continuing and developing our successful partnership with Emerald Airlines.”