The passenger who died was believed to be a 63-year-old man from Germany | Photo: AFP / Christof STACHE

Passengers on a Lufthansa flight experienced "absolute horror" as a man died mid-air after coughing up "litres of blood" on Thursday.

The incident took place on Flight LH773, which departed from Bangkok for Munich at 11:40 PM on Feb. 8. The male passenger, believed to be a 63-year-old German, didn't appear to be in a good state when he and his wife boarded the Lufthansa plane, according to witnesses.

Even though the man was heavily sweating and supposedly struggling to breathe as well, his wife told the cabin crew that her partner was just tired after running to catch the flight.

One of the passengers on board the Lufthansa flight, Martin Missfelder, claimed that the man's condition quickly worsened soon after the flight's take-off.

"A flight attendant then reacted and asked him if he was okay, she was very worried," said Mr. Missfelder's wife Karin, who was sitting with her husband behind the couple.

The pilot later intervened and called for a doctor over the loudspeaker. There was a Polish physician on board, who spoke to the struggling man and took his pulse before indicating he seemed OK.

However, soon after that, the man began spitting blood into a bag, before it began gushing out of his nose and mouth.

"It was absolute horror, everyone was screaming," said Mr. Missfelder, who also added that the man had lost "litres of blood" and it had splashed across the walls of the plane too.

The flight crew tried to resuscitate the man for around half an hour before he was declared dead.

The Airbus A380 plane, on a 12-hour journey to the Bavarian capital, then turned around and returned to the Thai capital.

"We confirm that on 8 February 2024 on flight LH773 (Airbus A380) from Bangkok to Munich a medical emergency of a passenger occurred on board.

"Although immediate and comprehensive first aid measures were taken by the crew and a doctor on board, the passenger died during the flight. After 1.5 hours of flight time, the crew decided to return to Bangkok, where the aircraft landed normally and safely.

"There, the instructions of the medical emergency services and the Thai authorities were followed. The passengers on this flight have since been rebooked on other alternative flights as it has been cancelled," a spokesperson for Lufthansa said.

The German carrier also paid condolences to the deceased passengers' families, and also apologised for the inconvenience caused to the passengers of the flight. Lufthansa also confirmed that all affected passengers were booked onto alternative flights for the journey back to Munich.