A Saudi Arabian airline has agreed to buy 16 aircraft from Canadian-based Bombardier in a £733m deal.
Wings for the firm's C-series aircraft are made at Queen's Island in east Belfast.
Newly-launched carrier SaudiGulf Airlines also has an option to buy 10 more single-aisle planes from Bombardier.
It comes as Bombardier announced the launch of the model was pushed back to the second half of 2015.
The first C-Series jetliner was originally scheduled to be delivered to customers in September, but the firm said it needed more testing.
Two years to set up an airline and a launch customer for a new aircraft type? This should be interesting
Mutt