Boeing yesterday delivered three new Next-Generation 737-800s to European carrier Hapagfly in one day. Hapagfly, based in Hannover Langenhagen, Germany, is a subsidiary of the TUI Group. The deliveries are part of a milestone order for 10 Boeing 737s placed by the TUI Group for Hapagfly in late 2004. The new airplanes are part of the carrier's fleet standardization plans, which include the replacement of its aging A310s with the advanced-technology 737-800. Hapagfly took delivery of an earlier 737-800 from the same order on March 25, totaling four deliveries in one week. The new 737s are fitted with Blended Winglets, which reduce aerodynamic drag, improve fuel efficiency and increase range. The Boeing 737 is the world's most popular jet airplane, with more than 6,100 sold worldwide.