It will be interesting how Boeing/Airbus/traditional carriers react when China fully enters the market with Comac-built/branded planes. Commercial flights of its first plane, the C919 are slated for 2021. Eh, the Chinese aren't a threat despite what McNerney thought. If nothing else the C919 isn't Comac's first attempt at an airliner, the ARJ21 was.
Airliners are extremely complex. Take a look at Mitsubishi. They've got experience building planes, turbines, etc. Yet Mitsubishi is still struggling with the MRJ, in large part because the MRJ is the first Japanese built airliner in an extraordinarily long time. As for the Chinese, McDonnell-Douglas sold tooling to the SAIC (now Comac) so that they could build licensed MD-80s (some of which are flying in the US). The tooling was eventually used to develop the ARJ21 and Comac still couldn't make it work well. There are a few ARJs flying in China, but even the domestic airlines don't want them. The Canadians tried their hand at a modern airliner with the C-series, and that pretty much bankrupted Bombardier.
China could really be set up to take a lot of commercial aircraft market share over the coming decades.
Even if (or when) Comac were magically able to produce a competitive airliner, there's more to selling planes than just building them. Support is a huge issue. The Russians have significant experience successfully building airliners and yet even with western turbofans Sukhoi couldn't find a market for their SuperJet. They sold a few to the Belgians and the Mexicans but those have largely stopped flying. Why? There's no support. Boeing and Airbus have huge support networks all over the globe. Comac has absolutely nothing like this in the works or in place.