The Boeing Co. is working with 787 launch customer All Nippon Airways to ready the Dreamliner for its first delivery in August or September.

Boeing and the carrier will fly a 787 to Japan the week of July 4, the two companies said Thursday. Japan-based ANA and Boeing will fly between airports

in Japan, simulating commercial flights the carrier will make when it receives the first Dreamliner.

“ANA is eager to introduce the innovative 787 Dreamliner to Japan,” said Shinichiro Ito, ANA’s chief executive officer. “Giving our employees the opportunity to gain experience with the airplane will help ensure a smoother entry into service later this year.”

This will be the 787’s first trip to Japan. ANA has 55 787s on order. Boeing’s mostly composite jet has been in flight testing since December 2009.

“We’ve put the airplane through its paces in a rigorous flight test program,” said Scott Fancher, Boeing’s 787 general manager.

Boeing originally had hoped to hand over the first 787 to ANA three years ago this month. Multiple delays have created skepticism among Boeing customers and industry observers whenever Boeing executives provide a new delivery date.

However, this latest delivery target — narrowed Thursday from the third quarter to August or September — has garnered confidence.

“I think September sounds like a pretty good date,” said analyst Scott Hamilton, with Issaquah-based Leeham Co.

Boeing still faces another hurdle in flight testing: extended twin engine operations certification, called ETOPS, which would allow 787 operators to fly the jet long distances without stopping. Earlier this week, Fancher said the company will begin flights for this certification in June.

Boeing has said it wants the Federal Aviation Administration’s OK for extended operation on the 787 before the company delivers the first Dreamliner to ANA. However, Hamilton noted that lacking the additional certification shouldn’t prevent Boeing from delivering the first 787 to Japan by September’s end. The carrier will fly the 787 on shorter flights until Japan’s aviation authorities also approve extended 787 flights.

After first delivery, Boeing has several other challenges on the 787: preparing dozens of already built 787s for delivery and ramping up production on the Dreamliner. But meeting its first delivery goal will be a major milestone for the company, which hopes to deliver up to 20 787s this year.

Boeing has 835 Dreamliners on order.