Once again United (UAL) - Get Report will use the world's most advanced airplanes on one of commercial aviation's most aspirational routes from what is now the most important developing U.S. hub.

Starting June 1, United will fly the Boeing (BA) - Get Report 787-9, the upgraded Dreamliner model, from San Francisco International Airport to Singapore. At 8,446 miles, the route will be the longest 787 route in the world as well as the longest scheduled flight by any U.S. carrier.

The flight will take 16 hours and 20 minutes westbound and 15 hours and 30 minutes eastbound.

Aspirational network planners "dream about services like this and wish we had the airplanes to do it," said Brian Znotins, United vice president of network. "So when we reach the confluence of an airplane with range capability and can fly the only non-stop from North America to Singapore, we will jump at that."

As a test of new frontiers in aviation, the SFO-Singapore flight compares with the SFO-Chengdu flight United began in June 2014, using a 787-8.

That was the first non-stop commercial flight ever from North America into the interior of China, and it was also enabled by the 787, because previously a bigger airplane was required to carry sufficient fuel. But a bigger airplane would have been too big for a new route.

When it started, the 6,857 mile SFO-Chengdu flight was the longest 787 flight to operate non-stop in both directions.

Boeing introduced the 787-8 in 2011; United partner All Nippon Airways flew the first flight. United put 219 seats on the aircraft, which has a range of 8,458 statute miles.

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Boeing delivered the first 787-9 in July 2014 to Air New Zealand, but ANA moved more quickly and flew the first commercial flight. United put 252 seats in its 787-9, which has a range of 8,786 miles.

Boeing has now delivered 366 Dreamliners, including 74 of the 787-9. On the Boeing earnings call Wednesday, Chief Financial Officer Greg Smith said, "As planned, 787-9 deliveries will notably exceed 787-8 deliveries in 2016."

United is putting the airplane together with its San Francisco hub in one of the U.S. airline industry's most dramatic hub buildups ever, recalling Continental's buildup of Newark as a trans-Atlantic hub and Delta's bankruptcy buildup of Atlanta as an international hub and not just a place to connect to Florida.


 "San Francisco has replaced Narita" in Tokyo as the airport where U.S.-Asia passengers make connections," Znotins said. "San Francisco has long been a Pacific hub, but 20 years ago you flew to Tokyo and you went beyond. But {(U.S.} passengers want to fly non-stop from the U.S."

In San Francisco, United has 268 daily departures to 92 destinations. The 20 international destinations include nine in Asia (three in China plus Hong Kong and Seoul) five in Latin America and four in Europe and five in Canada.

When Singapore and Xi'an are added, United will fly 787s from SFO to nine cities, including Sydney, Chengdu, Houston, Osaka, Taipei, Tel Aviv and Tokyo Haneda. Both Beijing and Shanghai are served with 747s. In July, Auckland will become the 10th 787 destination.

At one time, Singapore Airlines flew non-stop from Singapore to both Newark and Los Angeles using an Airbus A340. Both flights were discontinued in 2013, partially because the four-engine aircraft was a gas guzzler.

At 9,534 miles, the 18-and-a-half Singapore-Newark flight was the longest in the world. Singapore plans to restart the route in 2018 using the Airbus A350.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.