Delta Air Lines is passing on the Boeing 787 Dreamliner.

The Atlanta carrier said it has canceled an order for the high-profile new model, after previously postponing deliveries.

Delta had inherited the order for 787s through its 2008 merger with Northwest Airlines. The 787 orders were considered a significant part of Northwest’s assets at the time.

The question of what Delta would do with the order had been up in the air for years. In 2010, the airline announced it had decided to defer delivery of the 18 787-8 planes until 2020 and later.

Rivals United and American airlines, meanwhile, have both added the 787 to their fleets, as have dozens of foreign carriers.

When Delta this week announced the cancellation, Greg May, senior vice president of fleet, said in a written statement: “This business decision is consistent with Delta’s fleet strategy to prudently address our widebody aircraft needs.”

The list price for a 787-8 Dreamliner is $224.6 million, making the Delta order worth as much as $4 billion. Airlines typically get bulk discounts for large orders, however.

The Dreamliner, a long-haul jet used for international flights, has garnered attention for its fuel-efficiency and innovative features, including a light airframe made partially of carbon fiber composite.

It had been under development for years and its debut was hampered by numerous delays before entering service in 2012 with Japanese carrier All Nippon Airways as the launch customer.

The Delta cancellation is a hit to Boeing. Delta did not offer any detailed explanation, but it has also placed high-profile orders with competitor Airbus, including for the "extra wide-body" Airbus A350 to fly on international routes.

The A350, which Delta will start flying next year, is larger than the 787, also has a fuselage made partly of carbon-fiber composites and is known for its fuel-efficiency.

Delta, which has taken a more conservative approach to buying new planes than its competitors, said it still has orders for 120 Boeing 737-900ERs and is taking delivery of those planes.