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A gigantic, humpback-shaped cargo plane has been turning heads in the skies over the Seattle area for months as it's undergone hundreds of hours of flight tests.

It's about to become a more common sight in a lot more places, as it begins carrying large chunks of Boeing Co.'s new 787 Dreamliner from factories in Japan and Italy, South Carolina and Kansas to the company's widebody assembly plant here.

It's called the Dreamlifter — a lofty name for a jet whose bulbous fuselage has earned it no shortage of pot shots.

Scott Carson, Boeing Co.'s commercial airplanes chief, drew some hearty laughs last year when he told a banquet hall full of aviation enthusiasts it was a plane "only a mother could call pretty."

"Paint helps a little bit, but it's kind of like putting lipstick on a pig," quipped Mike Bair, head of Boeing's 787 program.

Others look past its odd appearance and see a marvel of aeronautical engineering and manufacturing logistics.

After toying with various design concepts, from a pod on top of the plane to a large side door, engineers decided to lop off the top of a 747-400 passenger plane, fatten up the fuselage, then add hinges to one side of the tail so it can swing open.

Boeing buys the 747s used, strips them down and turns them into Dreamlifters in Taipei. Once the top gets torn off, "it literally looks like a flatbed truck," said Mike Bunney, director of global logistics for the 787 program. "Some people have jokingly referred to it as Topless in Taipei."

Two Dreamlifters are flying as Boeing awaits certification from the Federal Aviation Administration. A third is being modified in Taipei, and a fourth is waiting its turn.

At 65,000 cubic feet, the Dreamlifter's cargo capacity is more than twice that of the 747 freighters that shipping companies like United Parcel Service Inc. fly.

A less eye-catching but equally important piece of the Dreamlifter puzzle is a long, 32-wheeled cargo loader that drives up to the open-tailed freighter and pulls out fuselage sections, wings, whatever shipment the plane is carrying.

The loader is "designed to be kind of one-stop shopping," Bunney said. "You can get parts in and out of the airplane then move them around the factory site with the same device, so it simplified the whole logistics process."

Without the Dreamlifter, Boeing would have to wait several weeks for certain 787 parts made entirely or mostly of light, sturdy carbon-fiber composites to arrive by sea, leaving "an unbelievable amount of in-process inventory out bobbing around on the ocean," Bair said.

Another problem: Some parts, like the wings and center fuselage, are so large they won't fit in standard shipping containers.

"If we had decided to do ocean shipping, we probably would've had to buy our own ships," Bair said.

This is the first time Boeing has designed a plane simply to play a supporting role in the production of another plane.

Airbus SAS has been flying its own superfreighter, nicknamed the "Beluga," since the mid-1990s to carry fuselage sections and wings from factories around Europe to its final assembly lines in Toulouse, France, and Hamburg, Germany.

Its fleet of five Belugas has also been used for charter missions to transport space station modules, chemical tanks, even a large French painting.

The Beluga is smaller than the Dreamlifter, though the bulge on the top half of its fuselage is much more pronounced than the Dreamlifter's, and it opens up at the nose rather than the tail.

Ironically enough, from the 1970s to early 1990s, Airbus ran a fleet of four modified Boeing 377 Stratocruisers nicknamed "Super Guppies" to transport plane parts from factories to final assembly plants.

Airbus spokeswoman MaryAnne Greczyn said the Beluga will be used to transport parts of the A350, the midsize jet Airbus is developing to compete with the 787, but the fuselage will probably have to be shipped some other way because it's expected to be too large for the Beluga.