Airbus forecasts put 20-year demand in the Bombardier CSeries category at just over 4,450 aircraft, although the total has stayed largely flat and represents a declining proportion of the single-aisle market.

While the combined figure for the 100- and 125-seat categories has fluctuated over the last five years, it essentially remains unchanged from the total of 4,363 given in its 2013 outlook.

This is despite a rise of more than 20% in the overall demand estimate for single-aisle aircraft.

Analysis of Airbus's forecasts over the course of 2013-17 shows that, as a result, the proportion of single-aisle demand in the CSeries size category has fallen from 22% to 18%.

Airbus has previously highlighted an upward shift in single-aisle aircraft size, pointing to the stronger demand for its A321 and A321neo.

Its A319 – developed for the 125-seat sector – had accounted for 17% of Airbus single-aisle orders at the beginning of 2013.

The airframer had pitched the re-engined A319neo against the CSeries, with chief operating officer for customers John Leahy insisting that its aircraft eliminated the business case for the Bombardier twinjet.

But net total orders for the A319, and its A319neo successor, have increased by just nine aircraft in the last five years.

Airbus has concentrated on its A320neo and A321neo airframes, pushing back certification of the A319neo to next year. The smallest member of its re-engined family has logged 51 orders.

The CSeries, despite struggling to accumulate orders during its development, nevertheless has a relatively better backlog of some 350 aircraft.

Chief executive Tom Enders suggested, while detailing Airbus's acquisition of a majority share in the programme, that the CSeries has suffered from customer uncertainty, rather than a lack of demand in the sector. He put the demand figure for such aircraft at about 6,000.

Source: Cirium Dashboard