A flight attendant has issued a stark warning to travellers after noticing a recurring mistake made by passengers on her flights.

Jetting Julia, a popular vlogger and cabin crew member, was prompted to issue the cautionary advice following an incident on a recent US flight where a passenger fell ill.

Julia recounted how the man began complaining of feeling “freezing cold” and was “visibly shaking” even before the plane took off.

A doctor on board assessed him, paramedics were called, and it was decided that he was unfit to fly that day.

The man then revealed to the crew that he had not eaten anything on the day of his flight a common error many travellers commit, reports the Mirror.

Julia emphasised: “It is really important to eat and drink on the days that you are travelling.

“It’s important to not fly on a completely empty stomach and to have a lot of fluids in your system just because when you’re flying you can get dehydrated.”

She further advised against flying on an entirely empty stomach and stressed the importance of staying hydrated as flying can often lead to dehydration.

According to London Gatwick Airport, flying can often make people feel dehydrated. It advises: “Air travel can make you dehydrated due to the pressurised nature of the cabins, so be sure to always drink plenty of water and fruit juice. Also avoid alcohol, fizzy drinks or drinks containing caffeine.”

Turkish Airlines has advised passengers to consume at least one meal containing seasonal fruits and vegetables before embarking on longer flights, due to potential bloating caused by changes in cabin pressure.

The airline stated: “On long-haul flights, changes in cabin pressure during take-off and landing can lead to health problems.”

They further explained: “Air pressure in the cabin is lower than at sea level. As cabin pressure falls while flying, gas starts to expand. As a result, you may feel pressure in your stomach or digestive system.”