The Chinese air force appears to have had enough of being held responsible for the country's notorious flight delays, or it is at least trying to shift the blame.

The largest cause of flight delays is poor airline management, not the air force, according to statistics issued through official media by “relevant departments.” And, contrary to common belief, civil aviation has plenty of air space, says a report by the China News Service, a state news agency. The lack of clear attribution in the report and its implication that the air force is not to blame for the country's increasingly unreliable air services both point to military authorship.

With poor airline timekeeping now a cause of popular discontent, it is not surprising that the air force is ducking for cover. Figures compiled by flight data provider FlightStats and widely published in China last month only confirmed what most Chinese frequent travelers could have guessed: of 35 major airports in the global survey, Beijing Capital International Airport had the most delays; Shanghai Pudong was the second-worst. Only 18% of flights at Beijing in the first half of this year left within 15 min. of their scheduled departure time, while Shanghai managed 29%.

Admittedly, those two cities are China's largest, with the most congested airspace. But across the nation, only 76% of flights were on time in 2012, the worst performance in five years, says the Civil Aviation Administration of China (CAAC).

For an authoritarian government obsessed with social stability, an alarming aspect of this is the frequency of disorderly confrontations between furious passengers and airport and airline staff, some verging on riots. Such disturbances seem increasingly common, although they are an old tradition in Chinese commercial aviation. (One night in 2006, this reporter spent extra hours on an already late aircraft when passengers refused to take their seats for takeoff; they demanded an explanation and apology for the delay from a suitably high airline official. Toward dawn, they got the apology; no one ever had an explanation.)

Airline management causes 42.3% of Chinese flight delays, say the “relevant departments” quoted by China News Service, while the volume of air traffic is responsible for 26.1%. The implication is that if airspace matched the traffic demands, there would be fewer delays—but still plenty, because the airlines could not prepare their aircraft to leave the gate in time. No details of airline ineptitude were offered.

Bad weather is blamed for 20.9% of delays, air force activities (exercises, presumably) for 7% and airport security for 3.7%.

The CAAC last month declared it would punish airlines whose flights were delayed when others from the same airport operated on time. It has made such threats before, but in a new policy it has named eight major airports as being immune from flow-control directives by other airports. According to the new rule, if an aircraft is ready to go from one of the big airports, the destination must accept it, weather and air force exercises permitting. Officials say the idea is to prevent the smaller airports from favoring “certain” carriers, probably meaning those that are locally based, and above all to ensure that passengers are not trapped in aircraft that cannot take off.

The destination airport can still keep the aircraft waiting in the air when it arrives, however. The CAAC seems to calculate that passengers will be more patient circling near their destination than sitting in a stationary aircraft. Accordingly, airlines are loading more fuel, say local media. Yet even if destination airports allow prompt landings, the effect of the rule will surely be only to give priority to flights from the big airports, delaying other flights instead; it does not create capacity.

The abysmal schedule performance by Chinese civil aviation is most commonly blamed on conservative aircraft separation rules combined with inadequate airspace allocation by the air force, which ultimately controls China's skies. But all airspace is in fact available for military and civil use, says the China News Service, again evidently reporting what the air force wants said. The space that is more or less permanently allocated to civil use is 34% of the country's total, it says, while the air force gets just 25% and there is little flying in the rest.

Much of the unused airspace is probably in China's vast and sparsely populated western zone. The calculation of the share enjoyed by civil aviation may be affected by new allocations of low-altitude space to general aviation.

The air transportation system is under great pressure from traffic growth, China News Service points out, with aircraft movements rising 29% at Beijing Capital over the past five years, 36% at Shanghai Pudong and 33% at Guangzhou Baiyun.