China’s first high-altitude variant of the C919 narrowbody jet has completed its maiden test flight at Shanghai Pudong International Airport, marking a step forward in the home-grown aircraft’s challenge to Boeing and Airbus.Derived from the standard C919 platform, the specialised variant features a shortened fuselage and enhanced systems engineered for operations in high-altitude regions, the Communist Party mouthpiece People’s Daily reported on Monday.The plane will undergo comprehensive...