The carrier will relocate its Dallas Fort Worth flights to Heathrow, securing the landing and take-off slots needed and seeing no reason to maintain its Gatwick outpost now that it has become possible to consolidate at Heathrow.
When the new EU-US Open Skies agreement comes into effect at the end of March, permission will be granted for airlines to fly any routes between the two zones, allowing transatlantic carriers to consolidate their services and rework their flight routes.
American Airlines spokesman Tim Smith said: "Other airlines are in the process of announcing new flights to Heathrow and switching some of their London capacity in that direction. All these things came together on this decision."
American currently has only three legal competitors on the Heathrow transatlantic route – United Airlines, British Airways and Virgin Atlantic – but the imminent removal of route and fare restrictions means the west London hub will be home to new competition.