Swiss International Air Lines (SWISS) has taken delivery of the first of 20 Bombardier CS300 aircraft it has on order.

SWISS, the launch operator for the smaller CS100, will become the first airline to operate both variants of the CSeries when the CS300 enters service on the Geneva-London Heathrow route June 1.

SWISS ultimately plans to have 10 CS100s and 20 CS300s in its fleet.

“With its 20 additional seats, this second model in the CSeries family ideally complements our current aircraft fleet, and gives us an optimal equipment mix for our European short- and medium-haul services,” SWISS CEO Thomas Klühr said. “Our first CS300 will be initially stationed in Geneva … In fact, our entire Geneva-based fleet will soon consist solely of Bombardier CSeries aircraft.”

SWISS previously took delivery of eight CS100s. Three CS300s have been delivered to Latvia’s airBaltic. The SWISS CS300 is the 12th CSeries aircraft delivered by Bombardier overall and the fifth delivered this year.

Bombardier plans to deliver 30-35 CSeries aircraft in 2017.