After a series of flight disruptions by angry or unruly passengers, Chinese media on Tuesday revealed a new menace to air travel in the country: fighting pilots.

Two of them came to blows in the cockpit of a China United Airlines (CUA) flight in June, the official news agency Xinhua reported.

Few details -- such as the route the budget airline was operating, or how many people were on board -- were available.

The incident only came to light when it was mentioned in passing in a Civil Aviation Administration of China (CAAC) announcement of CUA's punishment -- a 10 percent cut in its flying hours and a ban on new routes, Xinhua said.

The airline sought to play down concerns, saying the pilots only had "some physical contact" due to a misunderstanding and denying it escalated into a fight, the report said.

But CUA said the pair had been grounded for six months, Xinhua added.

Unruly passenger behaviour regularly makes headlines in Chinese media as air travel booms, with unfamiliar or drunken travellers even sometimes trying to open doors in mid-flight.

The industry also scores poorly for customer satisfaction, with constant flight delays -- airspace is controlled by the military -- topping the list of complaints.

In January Chinese police detained 25 angry passengers who opened aircraft emergency exit doors before take-off after their flight was delayed by snow.

The previous month, a budget flight from Thailand to China was forced to return to Bangkok after a Chinese passenger threw hot water at a cabin attendant.

CUA has had a string of safety incidents this year, including three in June and July that "seriously violated regulations", Xinhua cited the CAAC as saying.

In one of the country's most high-profile air accidents to be blamed on human error, the pilot of a Henan Airlines flight that crashed in 2010, killing 44 people, was jailed for three years for trying to land when he could not properly see the runway.