I had to think about that one, not having had a chink takeaway for a while.
The Chinese (or anybody else) could easily improve on most of today's WW2 flying objects; Cessnas and Pipers. To make big breakthroughs on reliability (long term maintenance costs) they would need to address the avionics front (a perpetual black hole for money); perhaps today's glass cockpits will turn out reliable enough but I seriously doubt it...
Their #1 issue would be whether they could sell into the USA (90% of the world market). Toyota/Honda have been "looking" for plenty long enough.