Deliveries of China’s first narrowbody passenger jet to the top three domestic airlines could be falling behind schedule, according to company financial reports, raising market speculation regarding potential disruptions to the model’s engine supply.Air China and China Eastern Airlines received one C919 aircraft each in the first half of the year despite their stated goals of adding 10 apiece in 2025, according to the reports.China Southern Airlines’ reports said the carrier expects 12 of the...