Delta Air Lines is to launch direct flights from London Heathrow to Boston and Miami at the end of March.
The airline will fly twice daily to Boston and once a day to Miami from March 27.
The slots at the London hub came up for grabs following the merger between British Airways and Iberia, who were required to give them up as part of the deal.
A spokesman for Delta said the airline had seen strong growth in 2010 and the move was a result of a healthy financial performance.
Delta is part of the Skyteam alliance, which holds the smallest amount of slots at Heathrow and the carrier used this argument to get the green light from both EU and US authorities.
by Dinah Hatch
