Etihad Airways equity partner Air Berlin will replace all seven of the 112-seat Embraer E190s flying for Austrian subsidiary Niki with an equal number of Airbus narrowbodies by the middle of next year, the German airline announced on Tuesday. Plans call for a gradual transition to be completed by June and involve the addition of five 150-seat Airbus A319s and two 180-seat A320s.

The company said the move will allow Niki to become more efficient “in terms of its network and cost structure.”

“Harmonizing our fleet will enable us to achieve increased productivity, lower costs per seat kilometer and more efficient flight operations,” said Air Berlin CEO Wolfgang Prock-Schauer.

“The standardization of our fleet is a bonus for Niki,” added Niki managing director Christian Lesjak. “It will allow us to operate more economically on the whole. And the increased overall capacity will also enable us to support an important trend. Vienna Airport has established itself as a hub for Air Berlin passengers for flights to Greece and Cyprus, for example.”

The Air Berlin group announced the “harmonization” of its fleet in September as one element of a restructuring program, part of which involved the cancelation of orders for 18 Boeing 737s and 15 Boeing 787s. It plans to replace all 45 of its existing Boeing 737s with Airbus narrowbodies by the end of 2016.