Norwegian will begin nonstop seasonal service to two French Caribbean islands from the US east coast in December, a move that will see the carrier add Baltimore/Washington and Boston to its network.

The carrier will serve both Guadeloupe and Martinique from New York John F Kennedy, Baltimore/Washington and Boston from 3 December. Norwegian will operate thrice weekly to each of the islands from JFK, and twice weekly from both Baltimore/Washington and Boston, all with Boeing 737-800s.

Norwegian chief executive Bjorn Kjos says the airline plans to operate on the routes seasonally and will gauge demand for potential year-round service. "We anticipate a lot of US passengers, and also passengers from Europe that will transfer onto these flights," he tells Flightglobal. A majority of the passengers are expected to be leisure customers.

Norwegian will be the only carrier operating on its new Caribbean routes. American Airlines is the only carrier offering nonstop service between mainland USA and both Guadeloupe and Martinique, with flights to Miami.

The two islands are overseas regions of France, and therefore covered by the US-EU open skies agreement, notes Kjos.

The new flights to Guadeloupe and Martinique follow Norwegian's previous announcement that it will begin service to San Juan from four European cities in November, as well to St Croix in the US Virgin Islands from London Gatwick in the same month.

Kjos says the new Caribbean flights will utilise the 737s that Norwegian would have parked during the European winter travel season, where demand is lower. "We park around 10 aircraft in the winter. We want to utilise our aircraft in other areas, that's why we are trying out operations to these French islands."

The French Caribbean routes will also give Norwegian the opportunity to study more long-haul service out of Boston and Baltimore/Washington in 2016, says Kjos. He sees potential for "high catchment routes" such as from Boston to London. Baltimore/Washington is also an attractive candidate for long-haul service to Europe with its proximity to the US capital, he adds.

Norwegian has a base at Gatwick. No airline flies nonstop between London Gatwick and either Boston or Baltimore/Washington. But British Airways operates nonstop between London Heathrow and both US cities. Delta Air Lines and Virgin Atlantic also offer London Heathrow service from Boston, schedules in Innovata show. From Washington Dulles, British Airways, United Airlines and Virgin Atlantic fly nonstop to Heathrow.

Norwegian serves five US mainland cities currently: New York JFK, Orlando, Fort Lauderdale, Los Angeles and Oakland. It will add Las Vegas in October.

Source: Cirium Dashboard