Cityjet has struck a deal with SAS to operate and crew eight aircraft for the Scandinavian carrier and buy its regional Blue 1 airline.
All Blue 1 staff will transfer to Cityjet to crew the new Bombardier CFJ900 jets, which will be painted in SAS' livery.
From March, the wet lease agreement will see Cityjet operate the SAS CFJ900s "on routes and at times when there is a need for smaller aircraft". The deal is for eight years with an option on a further six aircraft.
SAS said its "strategy is to offer frequent travellers a broad network with frequent flights to, from and within Scandinavia".
Rickard Gustafson, SAS president and CEO, said: "We are looking forward to working with Cityjet to further expand our regional route network and thereby strengthen SAS' offering to frequent travellers.
"The eight brand new CRJ900s from Cityjet will provide us with efficient and flexible production of regional flights that will complement SAS' production on the larger traffic flows."
Cityjet has acquired 100 per cent of the shares in SAS subsidiary Blue 1. Blue1's B717 fleet has been reduced to five and will cease operating by the end of the year.
Patrick Byrne, Cityjet's chairman of the board, said: "This is a fantastic opportunity for Cityjet to work with a leading airline such as SAS.
"We are looking forward to a long-term cooperation, where we will deliver a high level of quality in terms of efficiency and customer service for SAS passengers.
"We are also keen to benefit from the experience and knowledge of the Nordic airline industry that the acquisition of Blue 1 will give us."
Cityjet launched an 18-times weekly service between Cork and London City this week.