Aerospace giant Bombardier and its 4,000 workers in Northern Ireland have received a "tremendous endorsement" as a returning customer placed a new order worth up to $6bn (£4.5bn) for 60 of its C Series planes.
Bombardier will sell fast-growing European airline airBaltic 30 CS300 aircraft - the wings of which are made in Belfast - with options to buy another 30.
And Bombardier has also unveiled two new luxury business jets which will be part-made in Belfast.
The Canadian firm's two new aircraft are the Global 5500 and Global 6500.
The plane-maker's Belfast workforce already makes a range of parts - including the forward fuselage, engine nacelles and other components - for Bombardier's Global 5000 and Global 6000 business jets.
The latest C Series deal comes as Bombardier prepares for the closure of its sale of a majority stake in the C Series to rival Airbus. Around 1,000 of Bombardier’s 4,000-strong workforce here work on the C Series wings.
A spokeswoman for Bombardier in Belfast said: “We are currently focused on closing the partnership agreement with Airbus.
“We will communicate on that when everything is finalised but momentum continues to build with this latest order from airBaltic, which is great news for us.”
The airBaltic deal is more good news for Bombardier after it defeated a US legal challenge from rival Boeing earlier this year.
Bombardier said that based on the list price of the CS300 aircraft, the firm airBaltic order for 30 of the C Series is valued at approximately $2.9bn (£2.2bn). That would increase to nearly $5.9bn (£4.5bn) should all 60 planes be purchased.
Analyst Addison Schonland of Airinsight.com said the deal was a “tremendous endorsement” and signalled airBaltic’s growing confidence in the narrow-bodied passenger jet.
Fred Cromer, president of Bombardier Commercial Aircraft, said: “This significant reorder from our CS300 launch operator is a strong testimony to the aircraft’s exceptional in-service performance.
“Furthermore, we are proud that the CS300 has helped airBaltic maintain its position as one of the world’s most punctual airlines.
“The C Series aircraft is at the forefront of the small single-aisle market and airBaltic played a key role in demonstrating its value.
“In the last 18 months, we have witnessed airBaltic’s growing leadership in the market, and we wish the airline further success with its expanded CS300 fleet.”
According to reports in Canada, Bombardier signs were being removed from the C Series assembly plant at Mirabel in Montreal at the weekend as the Airbus deal entered its final stages.
One Canadian aerospace reporter said C Series employees are now segregated from the rest of staff.
Meanwhile, Bombardier unveiled its new Global 5500 and 6500 at industry event EBACE in Geneva. It also announced that the existing Global 7000 will be renamed the 7500.
As well as its work on the Global 5000 and 6000, Bombardier’s Belfast workforce also creates components including the composite horizontal stabiliser for the Global 7000.