The number is a record for the low-cost operator and they are ready to book for travel between November 2016 and March 2017.
The increase has been driven by the introduction of six new weekly flights to the programme while the operator offers low-cost flights from Gatwick to eight US destinations.
Routes from Gatwick now on sale include four weekly flights to Fort Lauderdale, five weekly flights to Los Angeles, a Saturday flight to Orlando and daily flights to New York while twice-weekly flights to Puerto Rico are also going back on sale.
Thomas Ramdahl, chief commercial officer for Norwegian, said: "Today Norwegian has made a record 75,000 long-haul seats available to buy on routes to the US for winter 2016 – helping the British public to secure the best possible deals by booking in advance.
“With eight low-cost routes to the US, Norwegian continues to provide Brits with cheaper transatlantic travel, all while flying passengers in high-quality comfort on the newest Dreamliner aircraft.
“Winter 2016 will be our busiest yet as Brits seek out our affordable flights to popular US destinations.”
The announcement comes as the airline prepares for the launch of two new Manchester routes this week.
The first of four weekly flights will take off for Malaga on Thursday while a twice-weekly service to Alicante launches on Friday.
