Hwang was just two when he last saw his father and knows him only through photographs, but he has spent much of his adult life campaigning for him.

A producer for South Korean broadcaster MBC, Hwang Won was starting a business trip on a domestic Korean Air flight from Gangneung to Seoul’s Gimpo airport on December 11, 1969.

Minutes after takeoff North Korean agent Cho Chang Hee slipped into the cockpit and diverted the plane to Pyongyang at gunpoint.

Survivors say three North Korean fighter jets escorted it in to land, and that Cho was met by army officers and driven away.

The 50 passengers and crew were blindfolded with handkerchiefs before they were taken off the plane.

The incident sparked international outcry, prompting a UN resolution denouncing the hijacking, and two months later 39 of those on board were repatriated, but Hwang’s father was not among them.

Returning passengers said Hwang Won had been dragged away after resisting efforts to indoctrinate them and questioning the North’s ideology.

The Red Cross has long demanded the return of the remaining 11 South Koreans, but Pyongyang has repeatedly denied abducting them, claiming some had chosen to stay.

Their plight soon dropped from public attention, but the impact on Hwang’s family has never faded.

“My life has been a cycle of misery,” said his son.