China has ordered the Hong Kong-based airline Cathay Pacific to suspend any staff who support pro-democracy protests in the territory, APA reports citing BBC.
Beijing's demand coincided with a peaceful rally at Hong Kong's airport, where thousands occupied a terminal.
Cathay also faced pressure online after China's state-run press fuelled a #BoycottCathayPacific hashtag, which trended on Chinese social media.
Hong Kong has seen weeks of protests over China's control of the territory.
The protests began about nine weeks ago over a proposed extradition bill between Hong Kong and mainland China and evolved into demands for greater freedoms.
Hong Kong is part of China but its citizens have more autonomy than those on the mainland. It has a free press and judicial independence under the so-called "one country, two systems" approach - freedoms activists fear are being increasingly eroded.