Staff morale is at an all-time low, he says. Everybody is paranoid. "Basically, I think there's no trust between crews and office staff as well right now, everybody (is) scared," he says.

On August 28, Cathay Pacific issued a revised version of its employee Code of Conduct, seen by CNN, which includes sections on social media posts, and encourages employees to "speak up" if they see breaches of the code as part of a "whistleblowing" policy.

Since then, Cathay staff tell CNN that dozens of people have been fired from the company.

In response to a request from CNN, Cathay Pacific said that every staff dismissal is made in accordance with relevant employment contracts. Their statement added that the company is required to follow the regulations "prescribed by the authorities in mainland China...there is no ground for compromise."

Whistleblowing culture

Now, the mood at the company is "very somber," according to another Cathay pilot, Jack, who also spoke to CNN on condition of anonymity.

"The majority are extremely supportive of the movement, but not all," Jack says.

Those who aren't, he adds, are now denouncing their colleagues.

"Some cabin crew support the government, and have given fellow workers' names to the company who have talked about supporting the protests and thence been terminated," Jack says. "The company has actively asked for whistleblowers to come forward, creating a divide amongst fellow employees."

The result, he says, is an increasing culture of fear.

"Everyone has deleted chat groups and social media (profiles) that have any mention of the protests," Jack says. "The cabin crew don't even want to talk about the protests in the open, let alone admit they attend protests."

Over the past few months, Cathay flights landing in China have also become subject to extra inspections by airport officials, Jack says.

"Checking every safety compliance of our aircraft in China is now very common," he says. "They are intense and stressful for crew."

Crew members are also going through extra scrutiny when they arrive in mainland China, he adds.

"Security checks have increased in intensity, personal phones have been inspected," Jack says. "Crew now leave their phone at home or take a second 'China' phone to work."

Many workers at Cathay have a name for this increasing unease: 'white terror.' They say it is seeping into every aspect of the business.

"In terms of the white terror, I would say it feels unsafe, it's uncertain," Cathay staff member Paul tells CNN, on condition of anonymity. "We wouldn't know if it's our last day today, because tomorrow when we come in, we may not even be able to get into the building anymore."

The phrase 'white terror' dates back to the French Revolution, and is often used to describe the mass persecution of dissidents in political crackdowns, including Taiwan's decades of martial law until 1987.

Paul believes that Cathay's drive to encourage whistleblowing has hallmarks of Chinese-style communism.

"(It) is almost like China's cultural revolution, you encourage people to sell out their peers," he says. "People can take your words or take your things out of context and they can still report you."

The turnaround within Cathay Pacific is particularly disturbing for people in Hong Kong, given the 73-year-old company has a reputation for excellence -- it was named Skytrax airline of the year four times -- and is a major employer in Hong Kong, with nearly 20,000 locally-based staff.

On a day-to-day level, it has created a working culture that is increasingly hard to bear, says Sam, a Cathay crew member who wished to remain anonymous.

"I would say that in Cathay right now, everybody is kind of in stealth mode," Sam says. "So whatever you do, whatever you say, you look around before you talk on the phone, you look around before you check your phone, and you would think about what you are going to say before you would say it."

Younger members of staff are particularly affected by this internal cultural shift, she says.

"The more junior crews will watch their mouth or just smile and nod because they are so scared to be reported," Sam says.

Cultural shift

Long time staff say no one is exempt from the shifting mood. A senior air steward and union organizer for Cathay Dragon, Rebecca Sy, was one of the first staff members to be dismissed under the new regime.

"At the beginning, I was shocked," Sy says. "Very disappointed, frustrated."

Sy had worked at Cathay Dragon, a low cost subsidiary airline, for 17 years, and says she had a good relationship with the company. She tells CNN she was called into a meeting, asked to identify three screenshots from her Facebook account, and was then fired on the spot.

She says she has attended some of the authorized protests in Hong Kong, but says her Facebook account did not break the company's code of conduct. In response to CNN, Cathay says they don't comment on individual cases of dismissal.

"It is my first job since my graduation from university," Sy says. "I really loved my job...to me it's very special."

But the mood at the company is changing rapidly, she says, as the staff are "so afraid and scared."

"They are all losing faith, losing hope with this company," Sy says. "(They) can't enjoy the freedom of speech."

It's a pattern that is being repeated at other workplaces in Hong Kong, she says.

"It's not just Cathay (which is) being targeted," Sy says, adding that it is happening in other businesses as well as hospitals and schools in the city.

Cathay is majority-owned by Swire Pacific. The Anglo-Hong Kong conglomerate, which was founded in 1816, maintains a diversified business portfolio -- including a large property portfolio across mainland China.

The company's capitulation to Beijing's demands sends a strong message about the power of China's financial hold over Hong Kong.

Lee Cheuk-yan, General Secretary of the Hong Kong Federation of Trade Unions, says he has also seen evidence of so-called 'white terror' in other sectors, including the banking industry.

"This is now widespread in Hong Kong, and something we are very much worried about because our political belief is being compromised," he says. "So if you want a job, if you want to have a secure living, you have to be pro-China....that would be disastrous for Hong Kong."

For many of the staff still working at Cathay, the dramatic change in dynamic has come as a surprise, especially for those who once respected the company's culture and ethos.

"I can say that Cathay Pacific (had) an open-minded culture," Paul says. "I can no longer say the same."

But he says the fear spreading through the company will not change what the staff believe in.

"Freedom of expression, and opinions, and freedom of speech, that's how my family raised me up to be," Paul says. "I am a person, in addition to an employee, so I just think that you might be able to silence us inside a company, but then you cannot just change our mind."