When we were kids in the midwest on summer nights we would build hot air ballons from the clear plastic bags they put over clothes from the cleaners.
We would build a light weight X frame on the bottom to support a small candle with the bag fastened to the X frame
We would seal up the top end of the bag and light the candle, let the bag fill up and then watch it float way and then read in the newspapers the next day about Flying Saucer sightings. Harmless fun until we did it in the fall and caught some farmers corn field on fire.
After that the alien space port was closed by my Dad.