The Northern Airport Authority had summoned Vu Anh Cuong, the director of a Ho Chi Minh City-based real estate company following accusations he had groped a woman on a Vietnam Airlines flight from Hanoi to HCMC on July 26.
"Cuong admitted to sexually harassing the woman ... and apologized to [her]," Tran Hoai Phuong, director of the Northern Airport Authority, said.
Cuong used gestures and words to violate the dignity of aviation staff and female passengers on the plane, forcing aviation authorities to impose on him the maximum fine provided for, he said.
Cuong was taken off the flight as it was preparing to take off after he was found to be drunk, sexually harassing the woman passenger and insulting a flight attendant.
Unlike rape, sexual harassment is not a criminal offense in Vietnam.
The issue is underreported and was not treated seriously until recently, when incidents like this one tend to raise big discussions on social media.
A 2014 survey of 2,000 Vietnamese women by the NGO ActionAid found 87 percent of women and girls had experienced sexual harassment in public.