Continental was one of the first major airlines to fly Boeing 757s on transatlantic routes. There have been some instances of range limitations on west-bound transatlantic flights due to strong headwinds resulting in a fuel stop which does not appear on the timetable, but these stops are not common. The use of the 757 with its smaller seating capacity allowed for "thin" routes (routes with less passenger traffic) to be economically viable. It allowed non-stop service from smaller cities, such as Belfast, Northern Ireland and Hamburg, Germany to the New York gateway. Previously, customers originating at these and similar cities needed to connect at European gateways like London Heathrow, Paris Charles de Gaulle, or Frankfurt, in order to travel to New York. United retains a number of these flight routes, mostly based out of Newark, including Newark-Hamburg, Newark-Dublin, and Newark-Berlin.