SHANGHAI—Chinese airlines were buffeted this summer by a series of cockpit blunders that put passengers’ lives at risk, pointing to what foreign pilots say are serious flaws in training as China’s booming aviation industry struggles to meet demand for flight crews.

The mishaps included a July 10 incident in which an Air China Boeing 737 en route to Dalian from Hong Kong plunged 25,000 feet after the pilots mistakenly disabled the cabin’s air supply. They were trying to deactivate an air-circulation system so they could smoke, but ended up triggering an emergency descent.

On Aug. 16, a Xiamen Airlines Boeing 737 jet lost its landing gear and an engine and skidded off the runway when its crew tried to land in Manila in heavy weather.

Two weeks later, a Beijing Capital Airlines Airbus A320 lost its front wheels and damaged an engine as it bounced three times along a runway in Macau. The pilots aborted the landing and diverted to Shenzhen.

These were among seven serious incidents involving Chinese airlines reported in July and August alone. Though there were no fatalities, the mishaps were significant enough in most cases to receive media coverage and be addressed publicly by China’s aviation authority and the airlines involved. The less-serious incidents were chronicled by aviation websites, and in internal airline and civil-aviation bulletins reviewed by The Wall Street Journal.