Where In The World Are Airlines Still Flying Trijet Passenger Planes?

The first trijet aircraft entered commercial service in the 1960s. Faced with rising fuel costs, airlines were looking for an aircraft that would be more fuel-efficient than four-engined aircraft such as the Boeing 707. Three-engined aircraft also had the advantage of being certified to fly for longer distances over water than their twin-engined counterparts. Eastern Air Lines, for example, was keen for the US manufacturer to develop an aircraft that it could deploy on its longer Caribbean routes.