In the past, we called LoiKrathong as Chong Pa Rieng- floating lantern of royal ceremony. It is a Brahman festival to worship Gods- Siva, Vishnu, and Brahma. When Thai people adopted Buddhism, they adapted this ceremony to honor the Buddhas cremated bone- the original Buddha at the second heaven ruler. They floated lantern to worship the foot-print of the Buddha on Nammathanati River beach in India.
The villagers in northern and north-eastern parts of Thailand often float lanterns. They are made of color paper. If they float in the afternoon, they will use smoke for floating lanterns while they use torch to set smoke in lanterns to float them in wind chill at night. We can see the light from lantern in the sky with moonshine and stars glitter at night, which is very beautiful.