Can someone explain the tradition of releasing balloons with candles inside for Buddha? What is the meaning? Is it a Theravada or a Mahayana tradition? When and why people do it?
Through a search I've found use of releasing lanterns to be common in a few Buddhist areas that host both traditions. In Burma (Myanmar) there is the Tazaungdaing festival, which is celebrated as a national holiday and marks the end of the rainy season. It also marks the end of the Kathina, during which monks are offered new robes and alms.
Most of them sound like lay practice to me. Many countries traditionally celebrate with balloon lanterns. Is there a specific festival you are referring to?