The COMAC C919 is a new narrowbody airliner developed by the Commercial Aircraft Corporation of China (COMAC). It was designed to compete with the Airbus A320 and Boeing 737 aircraft family; this is a challenging task for a new aircraft. There have been good early sales in China, but slow production, uncertainty in certification, and unproven performance will limit its potential. Boeing and Airbus still dominate Chinese fleets, of course, but this could look different in a few decades if things go right with the C919.