At least 78 flights at Chiang Mai airport will be cancelled on Friday and Saturday to avoid hazards posed by floating sky lanterns during the traditional Yi Peng festival.
Chiang Mai airport general manager Gp Cpt Manathanik Rakngam said airlines will cancel 58 domestic and 20 international flights over the two days.
Domestic airlines will also reschedule 53 flights and international carriers 26 flights during the same period, he added.
The annual Lanna-style Loy Krathong festival is highlighted by the launch of sky lanterns. It is held throughout the northern region.
In Chiang Mai, the province allows the hot-air lanterns to be flown from 7pm on Friday to 1am on Saturday, and smoke lanterns to take off from 10am to noon on Saturday.
Meanwhile, Bangkok deputy police chief Phanurat Lakboon said floating lanterns and fireworks as well firing bullets into the air are banned during the upcoming Loy Krathong festival.