Australia's Qantas on Friday cancelled a three billion US dollar order for 15 Boeing 787 Dreamliner aircraft, citing dramatic changes to the global economic environment.
Qantas said in a statement that it had reached agreement to "cancel orders for 15 B787-9s scheduled for delivery in 2014/2015."
Company CEO Alan Joyce said the cancellation had not been influenced by the delay of the aircraft's inaugural flight earlier this week due to a design flaw.
"Qantas announced its original B787 order in December 2005, and the operating environment for the world's airlines has clearly changed dramatically since then," he said.
The statement said Qantas and Boeing had also agreed to postpone delivery of a further 15 Dreamliners by four years.
"The latest delay is disappointing but ... we remain committed to the aircraft as the right choice for (budget offshoot) Jetstar's future international expansion, Qantas' growth, and as a replacement for Qantas' B767-300 fleet," Joyce said.
Boeing on Tuesday delayed the first flight and delivery of its 787 Dreamliner for the fifth time, to reinforce the aircraft's structure, and said a new schedule would be available in "several weeks".
Already nearly two years behind schedule, the carbon-composite Dreamliner has been touted to usher in an era of lighter, more fuel-efficient planes, and is seen as key to the aerospace giant's future.
The cancellation takes Qantas' total B787 orders from 65 to 50 by 2017, and follows a decision to more than halve its profit forecast in April and axe up to 1,750 jobs.
Qantas at that time deferred orders for four Airbus A380 superjumbos and 12 Boeing 737-800s, while saying it was in talks to delay delivery of 15 Dreamliners, due to a rapid and significant deterioration in the global economy.