BEIJING — An angry mob ransacks a terminal. A frustrated passenger tries to leave the plane while it taxis. A pilot, who has had it up to here, advises fliers to leave the plane and mill about the tarmac — and they do.

Welcome to China’s unfriendly skies. The world’s second-largest economy boasts some of the world’s worst flight delays and missed connections. Angry passengers have become such a fixture of flying in China that the government has developed a blacklist for the dangerously unruly.

Chinese leaders are aware of the problem. Spurred by the strain on the air traffic system as well as a slowing economy, China has begun a huge airport building project that could give the country 60 more airports beyond the current total of about 200 by 2020. It committed to spending $12 billion on airport construction and revamping this year alone.

A $12 billion airport under construction 30 miles southwest of Beijing’s center will eventually more than double the city’s air traffic capacity. The new airport, Daxing International, will have up to seven runways and 7.5 million square feet of floor space.