Second daily flights from Heathrow to Philadelphia and Los Angeles are being added by American Airlines from the end of the month.
The new transatlantic services will run to the US east coast city of Philadelphia from March 30 and Los Angeles from March 29.
The Boeing 757 flight to Philadelphia departs Heathrow at 8.20am and arrives at 11.40am local time, with the return departing at 9.45am and arriving in London at 10.10pm
The new Los Angeles service using a widebody Boeing 777 leaves London at 12.15pm and arrives at 3.30pm local time. The return leaves at 5.50pm and lands at Heathrow at 12.25pm the following day.