Air
Sky lanterns
Sky lanterns, originally from Thailand, are, in effect, little hot-air balloons. The open flame of the fuel cell that's held in a thin wire frame under the opening of a big, lightweight paper or fabric bag provides enough hot air to float the lantern high in the air. During Thai festivals, thousands are released at once to spectacular effect.
Even though they are sold outside of Thailand now, a number of places do not allow them because of serious concerns about starting fires in drought-stricken countryside. The lanterns fly free and land in unpredictable places.
I would urge you to find out what the laws are in your area and respect them - and follow all applicable safety precautions if you do launch these. Even the most beautiful lantern display is not worth the devastation of a wildfire.
In the meantime, enjoy lift-off with this little clip from the Pingxi Lantern festival in Taiwan: