Estonian operator Nordica's Regional Jet division is to expand its fleet with five more Bombardier CRJ900s next year.
The aircraft are being introduced under a co-operation with Scandinavian carrier SAS.
Three of the CRJ900s will be stationed in Tallinn and two in the Lithuanian capital Vilnius, says Nordica.
The aircraft, under a six-year wet-lease arrangement, will be put into operation in March 2020.
Regional Jet already operates on behalf of SAS with a pair of CRJ900s in Denmark and Sweden, plus eight ATR 72-600 turboprops.
The Estonian carrier is jointly owned by Nordica and Polish flag carrier LOT.
"We are now above our critical mass level which makes us a very competitive, flexible and sustainable regional capacity provider," says chief executive Jan Palmer.
Cirium fleets data also shows that Nordica operates Bombardier CRJ700s.