• A flight attendant working for Swiss Air has died after a plane's cabin filled with smoke mid-flight.
• On December 23, a flight from Bucharest to Zurich diverted due to engine issues and smoke.
• The staff member, who hasn't been named, died around a week after being taken to hospital.

A young Swiss International Air Lines flight attendant died after smoke started to fill the cabin and cockpit.

The flight — operating from Bucharest in Romania to Switzerland's Zurich on December 23 — made an emergency diversion to Graz in southern Austria after engine problems led smoke to spread through the plane, according to a press release by the airline.

The member of staff, who has not been named publicly, was airlifted to a hospital in Graz, where he was put into intensive care. He died on Monday, December 30.

"We are devastated at our dear colleague's death," Swiss CEO Jens Fehlinger said in a statement.

"We stand with one another at this truly difficult time; and we will be doing our utmost, together with the relevant authorities, to determine the causes involved," Oliver Buchhofer, the airline's chief operating officer added.

"We have many questions, and we want them answered," he added.

All 74 passengers on board the Airbus A220 were evacuated, and twelve received medical attention. All five crew members were placed under medical care.

"Our teams of experts are working hard over the festive season to evaluate all the facts and findings available, and are in close contact with the authorities," the airline said in a statement about the investigations into the incident.

The focus of the investigation is on the mechanical parts of the aircraft — like the engine — and the protective breathing equipment available to the cabin crew.

SWISS announced it was working with the relevant authorities, the engine manufacturer Pratt & Whitney, and the aircraft manufacturer Airbus.

"The initial findings point to a technical problem in one of the engines," it said in the press release, but the cause of the smoke has not yet been conclusively determined.

A special flight from Graz to Zurich was organized on the morning of Christmas Eve to get passengers to their destination.

• Some United Airlines employees at Denver International Airport fell ill after a holiday meal.
• The Association of Flight Attendants reported there were 24 cases of food poisoning symptoms.
• United Airlines is monitoring the situation and coordinating with health authorities.

Dozens of United Airlines employees at Denver International Airport fell ill after eating a meal provided by the airline on Christmas Day.

According to a letter from the Association of Flight Attendants, representing United workers in Denver and Phoenix, a total of 492 meals were served to flight attendants. Of those, there were 24 reports of symptoms connected to food poisoning.

Denver7 spoke with one flight attendant who said he felt sick and started to experience nausea and diarrhea shortly after eating the holiday plate of food. The employee said many of his colleagues who ate the meal were also ill afterward.

He told Denver7 that United Airlines has a strict policy requiring staff to submit a doctor's note within 48 hours when they call in sick during the holiday period.

A spokesperson from United Airlines told Business Insider: "United is monitoring reports from some employees about gastrointestinal symptoms following holiday meals served to Denver employees last Wednesday, and we are in contact with health authorities. There has been no impact on our operation."

The AFA initially reported that around 200 employees had been sick after eating the meal on Christmas Day, however, it said in its later letter that the actual number of reports was substantially lower.

"We recognize that there may be some who decided to "power through" or who may have been apprehensive about calling in sick over the holiday period, or who may have been on their way home and therefore did not miss work.

The union wrote that if staff had to call in sick and believe it was because of the meal, they should email their supervisor explaining they are among those with symptoms and that any points associated with the absence should be removed.

Although the letter said "there is no way to know for sure" if these were cases of food poisoning as there are viruses circulating that produce similar symptoms, management at the airport would keep monitoring the issue.