The first transatlantic flight by an airliner using pure sustainable aviation fuel (Saf) has been hailed as a "big step forward" ahead of its departure from Heathrow on Tuesday morning. Virgin Atlantic will operate the flight to New York JFK with a Boeing 787 Dreamliner aircraft.Virgin founder Sir Richard Branson, Transport Secretary Mark Harper and Virgin Atlantic chief executive Shai Weiss will be among the passengers on the flight, which is not carrying fare-paying travellers.The Civil Aviation Authority reviewed various aspects of the flight before granting an operating permit, including analysing ground tests with an engine running on 100% Saf.