Delta is to add a new service from Heathrow to Philadelphia for the summer 2015 season.
The US carrier, which operates a transatlantic joint venture with Virgin Atlantic, will begin the daily Heathrow-Philadelphia route from April 7, 2015 when it will use a Boeing 757 on the service.
The move will add extra competition on the route which is currently operated by both British Airways and US Airways.
Meanwhile US Airways has decided to cancel its Edinburgh to Philadelphia seasonal route for summer 2015 as sister carrier American Airlines adds a new daily service from the Scottish capital to New York JFK from May 7, 2015.
US Airways only began its summer-only Edinburgh to Philadelphia service in May 2014.