That security is supreme on flights is a well-known fact. It is equally well known that no one should tamper with any equipment in an airplane. And flight crew should be the last people to break this rule, comments China Daily writer Zhu Yuan.

Yet 13 empty and partly empty bottles of oxygen were found on two Cathay Pacific flights from Hong Kong to Toronto on Aug 17 and 18. Another empty bottle of oxygen was found on a flight operated by Cathay Dragon (a subsidiary of Cathay Pacific) before it took off for Kuala Lumpur on Saturday.

Investigators are yet to identify the suspects or whether they have any links with the illegal demonstrations in the Hong Kong Special Administrative Region, but the recent actions of some Cathay Pacific employees suggest their minds have been poisoned by anti-Chinese mainland ideas.

Although the airline has put 40 crew members on a "duty to be assigned" list and introduced a new policy requiring flight crew to conduct even stricter checks on flights every 60 minutes to ensure complete security, there is still enough reason for the public to be worried about security on Cathay Pacific flights.

In fact, on July 26, the pilot of a Cathay Pacific flight from Tokyo to Hong Kong, instead of informing passengers about the weather and flight condition, used the public address system to voice his support for the demonstrators, seriously violating work ethics.

True, even a pilot has the right to air his or her political views－but not on flights or at airports.

Perhaps owning up for the unethical and illegal behaviors of some of the airline's employees, John Slosar resigned as Cathay Pacific chairman on Wednesday, even though the airline said his resignation is due to "his retirement and that he is not aware of any disagreement with the board of the company".

Still, Cathay needs to focus more on beefing up security on flights rather than being lulled into a false sense of security. The airline should also ensure that its employees don't express support for the Hong Kong demonstrations while on duty, for by so doing they would not only break service rules but also could compromise flight security.

After all, whoever walks in integrity walks securely, but whoever takes crooked paths will be found out.