When I was a kid I made a 10ft long blimp from plans alone that was constructed with balsa wood and an envelope of plastic where each segment was hand soldered. It had a small meths burner underneath that provided the heat required to inflate and keep it aloft.
Unfortunately on the inaugral flight on my parents top garden the wind got a hold of it and the burner swung erratically catching the plastic alight and literally recreating a scale version of the Hindenburg tradgedy...
Looks like things are a little more sophistimicated nowadays. This thing moves through the air effortlessly like a giant Fin Fish.
Air Art from flip on Vimeo.