Chinese domestic flight delayed two hours after pair demand free upgrade and assault crew
Pilot forced to abort flight and return to terminal to allow police to board and drag away troublemakers

Two economy passengers on a domestic Chinese flight who demanded upgrades to first class, injured four cabin attendants and a security officer and delayed the plane for nearly two hours are being investigated by police, Hainan Airlines said in a statement on Tuesday.
The airline said it would take legal action against the two men, who were not named, and apply to the Civil Aviation Administration to have them added to a national black list of disgraced passengers who are banned from air travel in future.
The two men holding economy class tickets occupied seats in the first class cabin after boarding flight HU7041 from Taiyuan, in northern Shanxi province to the southern metropolis of Chongqing on Sunday.