China's massive civil aviation fleet is ageing faster than planes are being replaced, threatening to saddle airlines with higher costs, but orders for home-grown C919 jets could help stem the tide, according to the head of north Asia for the International Air Transport Association (Iata).

High maintenance and fuel costs squeeze Chinese airlines as replacement rates lag, while Comac’s home-grown model seen as buffer against supply-chain hurdles.

China's massive civil aviation fleet is ageing faster than planes are being replaced, threatening to saddle airlines with higher costs, but orders for home-grown C919 jets could…