The A340 was originally launched as a long range complement to the short range A320, and the medium range A330. Airbus’s problem was that regulations required twin engine aircraft to stay within 60 minutes flying time of a suitable diversion airport. This prevented Airbus’s twin jets from competing on long over-water routes. Four engines would fill that gap in their fleet.
Virgin Atlantic ran its first A340 service in August 2002, and their slogan for the 340, “4 Engines 4 LongHaul” inspired the title.