Qatar Airways is very interested in buying Bombardier Inc's CSeries jetliners, but needs to address commercial issues before it makes an order, the airline's chief executive said on Sunday.

Bombardier said in March, interest in the new CSeries 100- to 149-seat aircraft was helping fuel demand, but the big push would come later with the need to replace aging fleets.

We are still talking to Bombardier, we have certain commercial issues to be addressed by them and once that is addressed, Qatar Airways is still very interested in the CSeries, Akbar al-Baker told Reuters on the sidelines of an aviation conference in Doha.

The Montreal-based manufacturer, which competes with bigger rivals Boeing and Airbus , said at the time it believed when the economy improved, pushing up oil prices, many companies would retire their older fleets in favor of newer models.

Qatar Airways has previously said it is looking to boost the number of smaller planes in its fleet and in June ordered 24 Airbus A320 series, which can carry between 107 to 185 passengers.

Bombardier expects the fleet of aircraft with fewer than 150 seats in commercial operation to grow to 17,300 over the next 20 years from about 11,000.

Qatar Airways, the flagship carrier of the world's largest liquefied natural gas exporter, has a fleet of almost 70 planes.

The carrier hopes to add 42 planes in four years and has orders for more than 220 planes, worth $40 billion, as it looks to turn Doha into the Middle East's hub between East and West.

Baker said there was absolutely no change in its airplane orders, although it had no plans to order new aircraft at the Dubai Airshow in November.

As a matter of fact we are pushing our manufacturers to supply airplanes faster, Baker said.

(Reporting by Tamara Walid; writing by John Irish; editing by Natsuko Waki and Mike Nesbit)