When people talk about Concorde, they tend to describe it the way one might describe Princess Diana: charming, elegant, and classic. The retired supersonic passenger airliner, still _____ 31 _____ a remarkable achievement of the engineering, first entered service in 1976. It had the most powerful and efficient engines at supersonic speeds. During flight, it would stretch between 6 and 10 inches from its normal length, _____ 32 _____ the heating of the airframe. A special white paint was thus used to help reflect and radiate the heat. Concorde used to fly regularly from London and Paris to New York and Washington. It flew these routes in _____ 33 _____ half the time of other airlines. A trip from London to New York with Concorde took nearly three hours and thirty minutes as opposed to eight hours with Boeing 777 or Airbus 330. That is to say, it was not _____ 34 _____ for business people to take a day trip to New York and return home in London before pubs closed. With only 20 aircraft built, _____ 35 _____ , Concorde was not a success in terms of economic profit. After the aircraft's only crash in 2000 and the 911 terrorist attack in 2001, Concorde was retired in 2003, bringing to an end the era of supersonic passenger transportation. (Fill in blank 35)