Cathay became embroiled in Hong Kong's protests when China's civil aviation regulator demanded the airline suspend personnel who engaged in or supported illegal protests in Hong Kong from staffing flights into its airspace.
Shares in Cathay Pacific Airways fell more than 4 percent to close to a 10-year low on Monday after the Hong Kong flag carrier became caught in crosswinds between Beijing and pro-democracy groups in the Asian financial hub.
Increasingly violent protests since June have plunged Hong Kong into its most serious crisis in decades and are one of the biggest popular challenges to Chinese leader Xi Jinping since he came to power in 2012.
Cathay became embroiled on Friday when China's civil aviation regulator demanded the airline suspend personnel who engaged in or supported illegal protests in Hong Kong from staffing flights into its airspace, citing safety concerns.
Cathay shares lost 4.37 percent to HK$9.85 by the break in Hong Kong, with the carrier's parent company Swire Pacific Ltd plunging 5.26 percent to HK$77.50.
On Friday, Beijing's aviation regulator ordered Cathay to submit a list of the identities of staff working on flights to the mainland or passing through its airspace.
It warned any staff members involved in "illegal protests" would be banned from such flights.
A political Cathay?
Cathay's CEO Rupert Hogg said in a message to staff on Saturday that the airline was obliged to comply with the new rules set out by the Civil Aviation Administration of China (CAAC).
"Cathay Pacific Group's operations in mainland China are key to our business. In addition to flying in and out of mainland China, a large number of our routes both to Europe and to the USA also fly through mainland China airspace," Hogg wrote.
"We are therefore legally required to follow CAAC regulations and, as is the case with any notices issued by any regulatory authority having jurisdiction over us, we must and will comply."
Cathay appears to have become a target of Beijing's ire after some of its crew joined protests and media reported one of its pilots had been charged with rioting.
The carrier's chairman John Slosar has defended his staff's right to freedom of thought, saying "we certainly wouldn't dream of telling them what they have to think about something".
But Hogg cautioned staff about their behaviour.
"Though people may share different views, it is essential that we all respect each other, our customers and members of the public," he wrote.
Cathay has suspended a pilot who has been accused of rioting after allegedly participating in the Hong Kong protests.
And it said Saturday that it had fired two airport ground staff, without specifying why. Local media reported that they were accused of leaking the travel details of a Hong Kong police football team that was travelling to the mainland.