Low fare transatlantic flights from Edinburgh, Dublin and Shannon will be increased for the winter by Norwegian with 90,000 seats added.
However, flights from Cork to Providence and Belfast to New York will only operate until October, with the carrier saying it will continue to assess its route schedule for summer 2019.
The announcement came a day after British Airways owner International Airlines Group signalled a possible take over of Norwegian after acquiring a minority shareholding.
Daily transatlantic flights from Edinburgh will be maintained this winter by increasing New York frequency to a daily service, up from three flights a week last winter. Fares start at £149 on a 189-seat 737 MAX aircraft based at the Scottish airport.
The winter schedule from October 28 will see Norwegian maintain an increased summer schedule from Dublin to New York Stewart international airport and Providence with a double daily service and daily service respectively. Fares start at €129 to Providence and from €139 to New York.
Norwegian will run daily flights from Shannon to New York Stewart International this winter as the carrier increases its flights from two a week from the previous winter. Fares start at €139.
Norwegian will use existing aircraft based at Stewart International, deployed to operate the current summer schedule to Shannon, for the increased New York winter flights from the west of Ireland.
Chief commercial officer at Norwegian Thomas Ramdahl said: “Consumers can now benefit from more high-quality flights to the USA this winter as we focus on boosting services that reflect strong passenger demand.
“We’re giving passengers on both sides of the Atlantic more affordable choice, so we’re delighted to increase the number of flights that brings the US east coast closer to Ireland and Scotland this winter.”