With flight attendants on stage from each airline that has ordered the jet, the giant factory doors opened wide as the plane slowly moved into view to the strains of a theme song composed specially for the 787, which Boeing calls the Dreamliner.
"Our journey began some six years ago when we knew we were on the cusp of delivering valuable new technologies that would make an economic difference to our airline customers," Mike Bair, vice president and general manager of the 787 program, told the crowd.
"In our business, that happens every 15 years or so, so you've got to get it right."
Boeing Chief Executive Jim McNerney said the 787 will bring about a "dramatic improvement in air travel: to make it more affordable, comfortable and convenient for passengers, more efficient and profitable for airlines, and more environmentally progressive for our Earth."
Boeing has won more than 600 orders from customers eager to hold the jet maker to its promise that the midsize, long-haul jet will burn less fuel, be cheaper to maintain and offer more passenger comforts than comparable planes flying today.
The 787, Boeing's first all-new jet since airlines started flying the 777 in 1995, will be the world's first large commercial airplane made mostly of carbon-fiber composites, which are lighter, more durable and less prone to corrosion than aluminum.
To date, Boeing has won 677 orders for the 787, selling out delivery positions through 2015, two years after Airbus SAS expects to roll out its competing A350 XWB.
In a rare tip of the hat to the competition, Airbus congratulated Boeing on the 787, whose commercial success has chipped away at the edge the European plane maker once held over its American rival.
"Even if tomorrow Airbus will get back to the business of competing vigorously, today is Boeing's day, a day to celebrate the 787," Airbus co-CEO Louis Gallois said in a letter to Boeing Chairman and CEO James McNerney on Sunday.
"Today is a great day in aviation history. Whenever such a milestone is reached in our industry it is always a reflection of hard work by dedicated people inspired by the wonder of flight," the letter said.
Airbus customers forced it to do a costly redesign of the A350, which pushed back production. Airbus also has faced problems with its A380 superjumbo, which has been hit with delays that slashed profit projections for Airbus' parent company, European Aeronautic Defence & Space Co.