Zoom Airlines will begin services between Gatwick and Fort Lauderdale next May and add flights to San Diego in June.
Both services will operate twice a week, with departures to Fort Lauderdale in Florida on Thursdays and Sundays and to San Diego on Mondays and Fridays. Return fares to Fort Lauderdale will start from £399 and to San Diego from £449.
The Canadian-registered carrier already serves New York from Gatwick as well as Bermuda and several cities in Canada.
Zoom excludes business class, operating just economy and premium-economy cabins.
UK managing director Jonathan Hinkles said: “We fit 270 seats in a Boeing 767 when the average on a carrier with business class is about 200.”