Bombardier has revealed EgyptAir plans to buy up to 24 C-Series aeroplanes.
The agreement was announced at the Dubai Airshow.
EgyptAir has agreed to buy 12 aircraft, with purchase rights for an additional 12 - which Bombardier said could raise the value of the contract to nearly $2.2bn US.
It follows last month's news when Airbus acquired a majority stake in the C-Series programme.
Safwat Musallam, Chairman and CEO of EgyptAir, said: “We look forward to expanding our network with the CS300 and we are happy to see that the partnership announced with Airbus will bring added support to the C Series program.”
Bombardier employs around 4,000 people in Belfast.
Its president, Fred Cromer, said: “We’re thrilled that EgyptAir selected the CS300 aircraft to renew its fleet.”