An easyJet pilot warned passengers to get off a plane bound for Rhodes seconds before take-off, it has been reported.
About 19,000 people have been evacuated on the Greek island because of wildfires - with many forced to sleep at the airport - and a further 2,500 on Corfu.
There were an estimated 10,000 British tourists on Rhodes before evacuations began, where temperatures have hovered above the 35C mark.
The easyJet pilot gave people on board the flight from London Gatwick one last chance to disembark before heading for Rhodes, the BBC said.
Its reporter, Gwyn Loader, was on board the flight on Monday, which was less than a quarter full.
He said there were only 37 passengers on the plane, which had a capacity of 180.
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The BBC said the pilot made an announcement before take-off, giving passengers one last chance to get off the plane and rebook their flights for another time.
Loader said eight people took up the offer and got off the flight, including one boy who was crying.
The pilot said over the tannoy: “Travelling to Rhodes for a holiday at the moment is a terrible idea."
He pointed out that some people were "stranded and sleeping at the airport".
Watch: Foreign Office advice on Rhodes is 'stick close to your tour company'
The pilot said: "As far as I’m concerned, this flight is being operated on an emergency basis. If you want to get off flight, you are welcome to do so.
"I don’t know in what capacity you are travelling, but if you are travelling for leisure, my sincere recommendation is it’s a bad idea.”
While some British airlines and tour operators have cancelled flights in and out of Rhodes, others, such as easyJet and Ryanair, are operating as normal.
The pilot's warning came despite Greek officials saying Rhodes and Corfu are safe and remain open for business to tourists.
The UK government has stopped short of advising Britons not to travel to the two islands, saying: "If you are planning to travel to any areas affected by wildfires, please check with your travel operator or hotel prior to travel that the area you plan to visit."
Prime Minister Rishi Sunak said on Monday: “My paramount priority is the safety of British nationals.
“The most important thing is people remain in touch with their tour operators, there are lots of flights going back and forth to be able to bring people home, and if people are in touch with their tour operators they will get the information that they need.”
On Tuesday, housing secretary Michael Gove insisted Greece is safe for holidaymakers.
He denied to Times Radio that the Foreign Office has taken too relaxed an approach and said he plans to go on holiday in just over a week to the Greek island of Evia, which was also partially affected because of wildfires.
On Monday, local Greek officials claimed the fires in Corfu were started by arsonists.
Watch: British tourists describe return from Rhodes