The unknown man was in the business class section of a United Airlines flight when he began removing his hair with an electric razor.
Another passenger, Derek Gregory, shared a video of the incident on Instagram, writing: "I'm not sure whether to thank you for the feature or be embarrassed or that I was on the same plane as this person."
Two flight attendants saw the man and did nothing as they walked past him and social media users were quick to comment criticizing the cabin crew.
One commenter quipped: "Better still, they let him continue to do it. Instead of saying STOP THAT they ask if he wants a hot towel?"