Since November 1st, Swedes no longer need a permit to launch the hot air born lanterns into the night sky. Anyone living within 100 metres of any of the main airports, however, must warn flight control they want to send the Khom Loy lanterns skywards.
The trend has more than ground staff on the lookout, however, as the number of suspected UFO sightings have risen along with the rice-lantern trend - which keeps the organization UFO-Sverige (UFO-Sweden) busy over the festive period.
"A lot of the reports at New Year's are triggered by the Thai lanterns," UFO report investigator Tobias Lindgren told the TT news agency. "Every year, I investigate between 50 and 60 sightings. I expect to have a lot to do this year too."
The non-profit UFO investigators have looked into sightings of unidentified objects since 1970 and has as their stated aim "the ambition... to turn the UFO subject into an established and respected field of research."
On New Year's Eve, Lindgren pointed out, their expertise in some cases provides a sense of relief to people who have spotted something untoward on the horizon.
"People think the lanterns are UFOs, but I recognize them immediately. Some people are very relieved when they find out," he said.