The Chiang Mai international airport has cancelled 15 flights due to the Lantern festival in Chiang Mai. Another 36 flights are rescheduled due to the Lanna/Lantern festival in the North.
Loy Krathong festival coincides with Lanna festival in Northern Thailand where swarms of lanterns are launched into the air that could cause hazard to the aircraft therefore the airport authorities have implemented changes to avoid the air-balloon that could cause problems for the flights.
The flights have been rescheduled and all passengers are informed in advanced about it. Some flights are cancelled to ensure safety of the passengers and aircraft.
According to Bangkok post, the use of hot-air balloon will be permitted from 7 pm to 1 am on Monday and Tuesday and gas-fueled lanterns are permitted on Monday from 10 am to 12 pm.