Thais celebrate the Loi Krathong holiday by floating ceremonial baskets onto lakes and ponds, and sometimes by also releasing sky lanterns made from rice paper stretched over a thin frame, which are carried aloft by the hot air generated from a candle or fiery oil-soaked fuel.

Buddhist monks prepare to release sky lanterns in Chiang Mai.

But the country’s airports are growing increasingly worried about what might happen if one of the fiery khom loy lanterns were to get sucked into a jet engine—a very real fear given that some 1,400 lanterns landed near Chiang Mai’s airport last year. More than 150 flights in and out of Chiang Mai have been cancelled or delayed during the peak of the holiday, from Nov. 5 to Nov. 7, affecting about 20,000 passengers.

The government is also cracking down on fire lanterns, declaring a 5 km (3 mile) “no fly zone” around airports for the duration of the holiday. In addition to Chiang Mai, Bangkok and three other areas are affected.

“We are asking people to cooperate because only one lantern can bring down a plane,” Chiang Mai air traffic control boss Kiattisak Rienvatana told the Associated Press.

AP Photo/Wason Wanichakorn) Thai Buddhist monks release lanterns in Bangkok.

Thailand isn’t the only country dealing with the hazards inherent in launching large balls of fire wherever the winds might carry them: Last year a massive fire was sparked in Britain by a so-called Chinese lantern in the Wests Midlands. The lanterns, with a basic design that dates back to third century BC in China, have been banned in Washington, DC since 1892.