See more details of the flight, including video of the landing
at Boeing's website here
.
The first of its 10 new planes would enter the airline's fleet around the middle of next year.
It will replace older planes flying to Asia, Western Australia and holiday destinations in the Pacific.
The airline has not released details of the final cabin configuration, crucial for passenger comfort. The 787-9 can carry between 250 and 290 passengers and Air New Zealand planes will have business premier, premium economy and economy seating, including Skycouch seats.
Boeing said the today's test flight was the beginning a comprehensive flight-test programme required before certification.
The plane took off from Paine Field in Everett, north of Seattle and landed Boeing Field just south of the city flying at a restricted altitude and speed.
Chief pilot Randy Neville departed to the north, reaching an altitude of 20,400 feet (6218 metres) and an airspeed of 250 knots, or about 463kmph, which he said was customary for a first flight.
While the pilots tested the airplane's systems and structures, onboard equipment transmitted real-time data to a flight-test team on the ground in Seattle.
The aircraft tested today was powered by two Rolls-Royce Trent 1000 engines and it will be joined in flight tests by two additional airplanes, one of which will feature General Electric GEnx engines. Those airplanes are in the final stages of assembly in Boeing's Everett factory.
Over the coming months, the fleet will be subjected to a variety of tests and conditions to demonstrate the safety and reliability of the airplane's design, Boeing said.
Although the Dreamliner programme fell years behind schedule Boeing has set more realistic targets for the 787-9 and has been meeting them.
The 787-9 fuselage is 6m longer than the 787-8 and can fly an additional 300 nautical miles (555km) and promises to use 20 per cent less fuel than similarly sized planes - crucial for long haul carriers such as Air New Zealand where fuel is the single biggest cost.
With a range of flying up to 15,000km which would open up the possibility of flying into Brazil, India or deep into the United States.
The plane has a list price of close to $300 million although Air New Zealand will get a significant discount for its order by taking two of the initial test planes which will be refitted for passengers after testing and monitoring equipment is removed.
Outsourcing delays and design problems set the Dreamliner programme back three years until and battery fires led to the grounding of the 50-strong fleet around the world for three months earlier this year.
The original 787-8 was delivered in September 2011, nearly three years late because of production problems caused by outsourcing delays and design problems. The worldwide fleet of about 50 planes was grounded for almost four months this year after lithium batteries smouldered on two planes in January.
The redesigned battery system, which resolves the overheating problems, is built into the 787-9.
Boeing plans another stretched version of the plane, the 787-10 that would seat between 300 and 330 passengers.